<PAGE>

                                  EXHIBIT 10.68


                       LEASE AMENDMENT TO LEASE AGREEMENT
                         FOR THE EXPERIAN/TRW BUILDINGS

<PAGE>

                                 LEASE AMENDMENT


         AMENDMENT AGREEMENT dated this 10/th/ day of March, 1995 by and between
ALLEN OFFICE INVESTMENT LIMITED PARTNERSHIP, a Texas limited partnership (herein
called "Landlord"), having an address at 711 High Street, Des Moines, Iowa,
50392-1450, Attention: Commercial Real Estate Loan Administration, Reference No.
D-399815, and TRW INC., an Ohio corporation (herein called "Tenant"), having an
address at 500 City Parkway West, Orange, California, 92668, Attention: John L.
Dettbarn.

                                   WITNESSETH

         WHEREAS, by Agreement of Lease dated April 15, 1993 (the "Lease")
Landlord demised to Tenant and Tenant hired from Landlord those certain premises
described in the Lease upon the terms, provisions and conditions as in said
Lease more fully set forth therein; and

         WHEREAS, Landlord and Tenant desire to amend the Lease as hereinafter
set forth.

         NOW, THEREFORE, in consideration of the premises, the mutual covenants
and agreements hereinafter set forth and other good and valuable consideration,
the receipt and sufficiency of which are hereby acknowledged, the parties agree
that the Lease be and it is hereby amended as follows:

         1. From and on April 15, 1995 through and including October 15, 2010,
each of the Basic Rent payments as defined in Paragraph 5(a) of the Lease and
outlined pursuant to Exhibit B of the Lease shall be increased by $3,254.00 per
month and the Rent payment for February 15, 2010 shall be increased an
additional $657,551.60, for a total rental payment increase of $660,805.60. The
original Exhibit B is deleted in its entirety and inserted in lieu thereof is
the Exhibit B attached hereto and made a part hereof.

<PAGE>

         2. The Termination Values as defined in Paragraph 5(c) of the Lease and
outlined pursuant to Exhibit D of the Lease shall also be amended to reflect the
monthly rental increase of $3,254.00 as well as an additional lump sum payment
of $657,551.60. The original Exhibit D is deleted in its entirety and inserted
in lieu thereof is the Exhibit D attached hereto and made a part hereof.

         3. Except as modified hereby, the Lease is and shall remain in full
force and effect, in accordance with its terms.

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the day and year first above set forth.

      LANDLORD:                  ALLEN OFFICE INVESTMENT
                                 LIMITED PARTNERSHIP, a Texas
                                 limited partnership

                                 By:      Principal Mutual Life Insurance
                                          Company, an Iowa corporation, its
                                          sole general partner

                                          By:      /s/ Karen A. Pearston
                                             ---------------------------------
                                          Its:     Karen A. Pearston, Counsel
                                              --------------------------------


                                          By:      /s/ Thomas R. Pospisil
                                             ---------------------------------
                                          Its:     Thomas R. Pospisil, Counsel
                                              --------------------------------


      TENANT:                             TRW, INC., an Ohio corporation

                                          By:      /s/ Thomas A. Gasparini
                                             ---------------------------------
                                          Name:    Thomas A. Gasparini
                                               -------------------------------
                                          Title:   Assistant General Counsel
                                                ------------------------------
                                                   & Assistant Secretary

                                      -2-

<PAGE>

                                    EXHIBIT B
                                    ---------

                               BASIC RENT PAYMENTS

                                                          Rental
                    Date                                 Payment
                    ----                                 -------
                  11/15/93                          $   87,560.25
                  12/15/93                          $   87,560.25
                   1/15/94                          $  132,927.05
                   2/15/94                          $1,074,597.97
                   3/15/94                          $  178,293.86
                   4/15/94                          $  178,293.86
                   5/15/94                          $  178,293.86
                   6/15/94                          $  178,293.86
                   7/15/94                          $  178,293.86
                   8/15/94                          $  178,293.86
                   9/15/94                          $  178,293.86
                  10/15/94                          $  178,293.86
                  11/15/94                          $  178,293.86
                  12/15/94                          $  178,293.86
                   1/15/95                          $  178,293.86
                   2/15/95                          $  405,772.67
                   3/15/95                          $  178,293.86
                   4/15/95                          $  181,547.86
                   5/15/95                          $  181,547.86
                   6/15/95                          $  181,547.86
                   7/15/95                          $  181,547.86
                   8/15/95                          $  181,547.86
                   9/15/95                          $  181,547.86
                  10/15/95                          $  623,539.14
                  11/15/95                          $  178,830.97
                  12/15/95                          $  178,830.97
                   1/15/96                          $  178,830.97
                   2/15/96                          $  178,830.97
                   3/15/96                          $  178,830.97
                   4/15/96                          $  178,830.97
                   5/15/96                          $  178,830.97
                   6/15/96                          $  178,830.97
                   7/15/96                          $  178,830.97
                   8/15/96                          $  178,830.97
                   9/15/96                          $  178,830.97
                  10/15/96                          $  880,903.68
                  11/15/96                          $  174,515.39
                  12/15/96                          $  174,515.39
                   1/15/97                          $  174,515.39
                   2/15/97                          $  174,515.39

<PAGE>

                                   EXHIBIT B
                                   ---------

                          BASIC RENT PAYMENTS (cont.)

                   3/15/97                          $  174,515.39
                   4/15/97                          $  174,515.39
                   5/15/97                          $  174,515.39
                   6/15/97                          $  174,515.39
                   7/15/97                          $  174,515.39
                   8/15/97                          $  174,515.39
                   9/15/97                          $  174,515.39
                  10/15/97                          $  928,375.08
                  11/15/97                          $  169,881.48
                  12/15/97                          $  169,881.48
                   1/15/98                          $  169,881.48
                   2/15/98                          $  169,881.48
                   3/15/98                          $  169,881.48
                   4/15/98                          $  169,881.48
                   5/15/98                          $  169,881.48
                   6/15/98                          $  169,881.48
                   7/15/98                          $  169,881.48
                   8/15/98                          $  169,881.48
                   9/15/98                          $  169,881.48
                  10/15/98                          $  979,348.12
                  11/15/98                          $  164,905.75
                  12/15/98                          $  164,905.75
                   1/15/99                          $  164,905.75
                   2/15/99                          $  164,905.75
                   3/15/99                          $  164,905.75
                   4/15/99                          $  164,905.75
                   5/15/99                          $  164,905.75
                   6/15/99                          $  164,905.75
                   7/15/99                          $  164,905.75
                   8/15/99                          $  164,905.75
                   9/15/99                          $  164,905.75
                  10/15/99                          $1,034,081.08
                  11/15/99                          $  159,563.00
                  12/15/99                          $  159,563.00
                   1/15/00                          $  159,563.00
                   2/15/00                          $  159,563.00
                   3/15/00                          $  159,563.00
                   4/15/00                          $  159,563.00
                   5/15/00                          $  159,563.00
                   6/15/00                          $  159,563.00
                   7/15/00                          $  159,563.00
                   8/15/00                          $  159,563.00
                   9/15/00                          $  159,563.00

<PAGE>

                                    EXHIBIT B
                                    ---------

                           BASIC RENT PAYMENTS (cont.)

                10/15/00                          $1,092,851.31
                11/15/00                          $  153,826.16
                12/15/00                          $  153,826.16
                 1/15/01                          $  153,826.16
                 2/15/01                          $1,864,290.70
                 3/15/01                          $  143,312.08
                 4/15/01                          $  143,312.08
                 5/15/01                          $  143,312.08
                 6/15/01                          $  143,312.08
                 7/15/01                          $  143,312.08
                 8/15/01                          $  143,312.08
                 9/15/01                          $  143,312.08
                10/15/01                          $  143,312.08
                11/15/01                          $  143,312.08
                12/15/01                          $  143,312.08
                 1/15/02                          $  143,312.08
                 2/15/02                          $1,986,470.89
                 3/15/02                          $  131,982.33
                 4/15/02                          $  131,982.33
                 5/15/02                          $  131,982.33
                 6/15/02                          $  131,982.33
                 7/15/02                          $  131,982.33
                 8/15/02                          $  131,982.33
                 9/15/02                          $  131,982.33
                10/15/02                          $  131,982.33
                11/15/02                          $  131,982.33
                12/15/02                          $  131,982.33
                 1/15/03                          $  131,982.33
                 2/15/03                          $2,118,129.58
                 3/15/03                          $  119,773.65
                 4/15/03                          $  119,773.65
                 5/15/03                          $  119,773.65
                 6/15/03                          $  119,773.65
                 7/15/03                          $  119,773.65
                 8/15/03                          $  119,773.65
                 9/15/03                          $  119,773.65
                10/15/03                          $  119,773.65
                11/15/03                          $  119,773.65
                12/15/03                          $  119,773.65
                 1/15/04                          $  119,773.65
                 2/15/04                          $2,260,002.07
                 3/15/04                          $  106,617.85
                 4/15/04                          $  106,617.85

<PAGE>

                                   EXHIBIT B
                                   ---------

                          BASIC RENT PAYMENTS (cont.)

                   5/15/04                          $  106,617.85
                   6/15/04                          $  106,617.85
                   7/15/04                          $  106,617.85
                   8/15/04                          $  106,617.85
                   9/15/04                          $  106,617.85
                  10/15/04                          $  106,617.85
                  11/15/04                          $  106,617.85
                  12/15/04                          $  106,617.85
                   1/15/05                          $  106,617.85
                   2/15/05                          $2,412,880.73
                   3/15/05                          $   92,441.44
                   4/15/05                          $   92,441.44
                   5/15/05                          $   92,441.44
                   6/15/05                          $   92,441.44
                   7/15/05                          $   92,441.44
                   8/15/05                          $   92,441.44
                   9/15/05                          $   92,441.44
                  10/15/05                          $   92,441.44
                  11/15/05                          $   92,441.44
                  12/15/05                          $   92,441.44
                   1/15/06                          $   92,441.44
                   2/15/06                          $2,577,619.40
                   3/15/06                          $   77,165.26
                   4/15/06                          $   77,165.26
                   5/15/06                          $   77,165.26
                   6/15/06                          $   77,165.26
                   7/15/06                          $   77,165.26
                   8/15/06                          $   77,165.26
                   9/15/06                          $   77,165.26
                  10/15/06                          $   77,165.26
                  11/15/06                          $   77,165.26
                  12/15/06                          $   77,165.26
                   1/15/07                          $   77,165.26
                   2/15/07                          $2,755,138.16
                   3/15/07                          $   60,703.98
                   4/15/07                          $   60,703.98
                   5/15/07                          $   60,703.98
                   6/15/07                          $   60,703.98
                   7/15/07                          $   60,703.98
                   8/15/07                          $   60,703.98
                   9/15/07                          $   60,703.98
                  10/15/07                          $   60,703.98
                  11/15/07                          $   60,703.98

<PAGE>

                                   EXHIBIT B
                                   ---------

                          BASIC RENT PAYMENTS (cont.)

                  12/15/07                          $   60,703.98
                   1/15/08                          $   60,703.98
                   2/15/08                          $2,946,428.45
                   3/15/08                          $   42,965.67
                   4/15/08                          $   42,965.67
                   5/15/08                          $   42,965.67
                   6/15/08                          $   42,965.67
                   7/15/08                          $   42,965.67
                   8/15/08                          $   42,965.67
                   9/15/08                          $   42,965.67
                  10/15/08                          $   42,965.67
                  11/15/08                          $   42,965.67
                  12/15/08                          $   42,965.67
                   1/15/09                          $   42,965.67
                   2/15/09                          $3,152,558.64
                   3/15/09                          $   23,851.26
                   4/15/09                          $   23,851.26
                   5/15/09                          $   23,851.26
                   6/15/09                          $   23,851.26
                   7/15/09                          $   23,851.26
                   8/15/09                          $   23,851.26
                   9/15/09                          $   23,851.26
                  10/15/09                          $   23,851.26
                  11/15/09                          $   23,851.26
                  12/15/09                          $   23,851.26
                   1/15/10                          $   23,851.26
                   2/15/10                          $4,032,231.59
                   3/15/10                          $    3,254.00
                   4/15/10                          $    3,254.00
                   5/15/10                          $    3,254.00
                   6/15/10                          $    3,254.00
                   7/15/10                          $    3,254.00
                   8/15/10                          $    3,254.00
                   9/15/10                          $    3,254.00
                  10/15/10                          $    3,254.00

<PAGE>

                                    EXHIBIT D
                                    ---------
                               TERMINATION VALUES


                     Date                         Termination Value

                    4/15/93                         31,860,846.10
                    5/15/93                         32,057,696.22
                    6/15/93                         32,255,717.54
                    7/15/93                         32,452,983.57
                    8/15/93                         32,651,016.22
                    9/15/93                         32,851,812.21
                   10/15/93                         33,051,417.04
                   11/15/93                         33,166,231.02
                   12/15/93                         33,283,429.19
                    1/15/94                         33,352,313.96
                    2/15/94                         32,480,860.59
                    3/15/94                         32,493,234.26
                    4/15/94                         32,505,288.47
                    5/15/94                         32,517,016.00
                    6/15/94                         32,528,719.16
                    7/15/94                         32,538,493.07
                    8/15/94                         32,556,592.43
                    9/15/94                         32,589,739.45
                   10/15/94                         32,621,284.68
                   11/15/94                         32,653,117.38
                   12/15/94                         32,685,240.15
                    1/15/95                         32,715,751.80
                    2/15/95                         32,519,062.68
                    3/15/95                         32,874,664.79
                    4/15/95                         32,901,987.49
                    5/15/95                         32,927,945.78
                    6/15/95                         32,954,141.98
                    7/15/95                         32,978,963.51
                    8/15/95                         33,004,012.62
                    9/15/95                         33,029,291.38
                   10/15/95                         32,611,195.87
                   11/15/95                         32,635,310.81
                   12/15/95                         32,659,646.93
                    1/15/96                         32,682,591.50
                    2/15/96                         32,705,746.59
                    3/15/96                         32,729,114.15
                    4/15/96                         32,752,696.12
                    5/15/96                         32,775,309.25
                    6/15/96                         32,798,129.93

<PAGE>

                                   EXHIBIT D
                               TERMINATION VALUES

                    Date                           Termination Value

                   7/15/96                          32,819,974.86
                   8/15/96                          32,842,020.36
                   9/15/96                          32,864,268.28
                  10/15/96                          32,183,462.55
                  11/15/96                          32,204,924.87
                  12/15/96                          32,226,584.33
                   1/15/97                          32,247,257.52
                   2/15/97                          32,268,120.67
                   3/15/97                          32,289,175.54
                   4/15/97                          32,310,423.88
                   5/15/97                          32,331,026.57
                   6/15/97                          32,351,818.64
                   7/15/97                          32,371,960.94
                   8/15/97                          32,392,288.44
                   9/15/97                          32,412,802.85
                  10/15/97                          31,678,805.29
                  11/15/97                          31,698,850.12
                  12/15/97                          31,719,079.30
                   1/15/98                          31,738,653.66
                   2/15/98                          31,758,408.13
                   3/15/98                          31,778,344.35
                   4/15/98                          31,798,463.99
                   5/15/98                          31,818,007.22
                   6/15/98                          31,837,730.31
                   7/15/98                          31,856,873.40
                   8/15/98                          31,876,192.75
                   9/15/98                          31,895,689.96
                  10/15/98                          31,105,138.50
                  11/15/98                          31,124,227.90
                  12/15/98                          31,143,493.12
                   1/15/99                          31,162,174.24
                   2/15/99                          31,181,027.49
                   3/15/99                          31,200,054.44
                   4/15/99                          31,219,256.69
                   5/15/99                          31,237,952.85
                   6/15/99                          31,256,821.33
                   7/15/99                          31,275,180.71
                   8/15/99                          31,293,709.37
                   9/15/99                          31,312,408.86
                  10/15/99                          30,461,422.42

<PAGE>

                                   EXHIBIT D
                               TERMINATION VALUES

                    Date                          Termination Value

                  11/15/99                          30,479,779.08
                  12/15/99                          30,498,305.05
                   1/15/00                          30,516,318.89
                   2/15/00                          30,534,498.94
                   3/15/00                          30,552,846.74
                   4/15/00                          30,571,363.84
                   5/15/00                          30,589,782.95
                   6/15/00                          30,608,372.04
                   7/15/00                          30,626,863.84
                   8/15/00                          30,645,526.31
                   9/15/00                          30,664,361.01
                  10/15/00                          29,749,812.40
                  11/15/00                          29,768,725.08
                  12/15/00                          29,787,812.32
                   1/15/01                          29,806,806.90
                   2/15/01                          28,115,512.30
                   3/15/01                          28,134,859.20
                   4/15/01                          28,154,384.69
                   5/15/01                          28,175,110.48
                   6/15/01                          28,196,027.47
                   7/15/01                          28,218,157.48
                   8/15/01                          28,240,491.51
                   9/15/01                          28,263,031.45
                  10/15/01                          28,286,799.24
                  11/15/01                          28,310,786.04
                  12/15/01                          28,334,993.85
                   1/15/02                          28,360,444.77
                   2/15/02                          26,542,971.28
                   3/15/02                          26,568,893.14
                   4/15/02                          26,595,053.73
                   5/15/02                          26,622,638.07
                   6/15/02                          26,650,476.33
                   7/15/02                          26,679,753.68
                   8/15/02                          26,709,300.40
                   9/15/02                          26,739,118.97
                  10/15/02                          26,770,394.73
                  11/15/02                          26,801,958.13
                  12/15/02                          26,833,811.82
                   1/15/03                          26,867,141.31
                   2/15/03                          24,914,629.97

<PAGE>

                                   EXHIBIT D
                               TERMINATION VALUES

                    Date                          Termination Value

                   3/15/03                          24,948,575.10
                   4/15/03                          24,982,832.30
                   5/15/03                          25,018,762.69
                   6/15/03                          25,055,023.27
                   7/15/03                          25,092,975.34
                   8/15/03                          25,131,276.08
                   9/15/03                          25,169,928.68
                  10/15/03                          25,210,294.62
                  11/15/03                          25,251,031.29
                  12/15/03                          25,292,142.08
                   1/15/04                          25,334,988.69
                   2/15/04                          23,238,000.27
                   3/15/04                          23,281,637.28
                   4/15/04                          23,325,674.92
                   5/15/04                          23,371,664.15
                   6/15/04                          23,418,075.50
                   7/15/04                          23,466,460.11
                   8/15/04                          23,515,288.72
                   9/15/04                          23,564,565.39
                  10/15/04                          23,615,841.50
                  11/15/04                          23,667,588.02
                  12/15/04                          23,719,809.28
                   1/15/05                          23,774,056.87
                   2/15/05                          21,522,539.14
                   3/15/05                          21,577,786.42
                   4/15/05                          21,633,540.42
                   5/15/05                          21,691,556.73
                   6/15/05                          21,750,105.05
                   7/15/05                          21,810,941.18
                   8/15/05                          21,872,335.07
                   9/15/05                          21,934,291.82
                  10/15/05                          21,998,567.52
                  11/15/05                          22,063,432.40
                  12/15/05                          22,128,891.83
                   1/15/06                          22,196,702.23
                   2/15/06                          19,779,956.11
                   3/15/06                          19,849,015.11
                   4/15/06                          19,918,707.00
                   5/15/06                          19,991,007.99
                   6/15/06                          20,063,971.47

<PAGE>

                                   EXHIBIT D
                               TERMINATION VALUES

                    Date                          Termination Value

                   7/15/06                          20,139,573.92
                   8/15/06                          20,215,869.00
                   9/15/06                          20,292,863.04
                  10/15/06                          20,372,532.86
                  11/15/06                          20,452,932.46
                  12/15/06                          20,534,068.51
                   1/15/07                          20,617,918.18
                   2/15/07                          18,024,562.89
                   3/15/07                          18,109,955.48
                   4/15/07                          18,196,130.13
                   5/15/07                          18,285,300.94
                   6/15/07                          18,375,288.29
                   7/15/07                          18,468,306.60
                   8/15/07                          18,562,176.58
                   9/15/07                          18,656,906.03
                  10/15/07                          18,754,709.74
                  11/15/07                          18,853,408.81
                  12/15/07                          18,953,011.45
                   1/15/08                          19,055,732.85
                   2/15/08                          16,273,670.06
                   3/15/08                          16,378,280.62
                   4/15/08                          16,483,848.73
                   5/15/08                          16,592,892.44
                   6/15/08                          16,702,934.17
                   7/15/08                          16,816,492.33
                   8/15/08                          16,931,089.72
                   9/15/08                          17,046,735.83
                  10/15/08                          17,165,949.54
                  11/15/08                          17,286,254.11
                  12/15/08                          17,407,659.51
                   1/15/09                          17,532,685.10
                   2/15/09                          14,549,261.64
                   3/15/09                          14,676,585.53
                   4/15/09                          14,805,074.35
                   5/15/09                          14,937,570.18
                   6/15/09                          15,071,278.13
                   7/15/09                          15,209,040.72
                   8/15/09                          15,348,063.50
                   9/15/09                          15,488,358.01
                  10/15/09                          15,632,767.27

<PAGE>

                                   EXHIBIT D
                               TERMINATION VALUES

                    Date                          Termination Value

                  11/15/09                          15,778,497.41
                  12/15/09                          15,925,560.50
                   1/15/10                          16,076,800.14
                   2/15/10                          12,221,042.69
                   3/15/10                          12,365,842.83
                   4/15/10                          12,511,967.59
                   5/15/10                          12,666,807.61
                   6/15/10                          12,823,063.83
                   7/15/10                          12,988,127.71
                   8/15/10                          13,154,701.03
                   9/15/10                          13,322,797.58
                  10/15/10                          13,500,000.01