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                                                                   EXHIBIT 10.53

                              FIRST AMENDMENT TO
                                LOAN AGREEMENT

          THIS FIRST AMENDMENT TO LOAN AGREEMENT (this "Amendment") is made as
                                                        ---------
of March 27, 2000, by and among between ZEFER Corp., a Delaware corporation (the
"Borrower"), and GTCR Capital Partners, L.P., a Delaware limited partnership
 --------
(the "Lender"). Except as otherwise indicated, capitalized terms used herein and
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not otherwise defined shall have the meanings ascribed to such terms in the Loan
Agreement (as defined below).

          WHEREAS, the Borrower and the Lender are parties to that certain Loan
Agreement, dated as of November 24, 1999 (the "Loan Agreement"), pursuant to
                                               --------------
which the Borrower and the Lender have agreed that the Lender shall make Loans
to the Borrower on the terms and conditions set forth therein; and

          WHEREAS, the Borrower and the Lender desire to make certain amendments
to the Loan Agreement in accordance with Section 11.3 thereof.

          NOW, THEREFORE, in consideration of the foregoing recitals and the
respective agreements set forth herein, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto agree to amend the Loan Agreement as
follows:

     1.   Subsection 2.2.3 of the Loan Agreement is hereby amended by adding at
the end thereof the following:

          "Notwithstanding the foregoing, the Lender's obligation to make any
additional Loans to the Borrower hereunder shall terminate upon the consummation
of an initial public offering of the Borrower's equity securities."

     2.   Subsection 3.5.3 of the Loan Agreement is hereby amended by deleting
it in its entirety and by adding the following in its place:

     3.5.3.    Public Offering.  The Borrower shall immediately apply the Net
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Public Offering Proceeds received from the initial public offering of its equity
securities pursuant to an effective registration statement under the Securities
Act in the following order and manner: (i) first, the Net Public Offering
Proceeds shall be used to fully repay the Harris Indebtedness; (ii) second, an
additional amount of Net Public Offering Proceeds not to exceed $23,400,000
shall be retained by the Borrower for working capital and other general
corporate purposes; (iii) third, an additional amount of Net Public Offering
Proceeds not to exceed $33,200,000 in the aggregate shall be divided evenly with
(a) one-half of such amount applied to repay the Loans and (b) the other half of
such amount retained by the Borrower for working capital and other general
corporate purposes; and (iv) fourth, the remaining Net Public Offering Proceeds
will be applied to repay the Loans.  All payments on the Loans under this
subsection 3.5.3 will be applied first to accrued and unpaid interest (including
Capitalized Interest) outstanding on the Loans and then to principal.  To the
extent the
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Net Public Offering Proceeds from the Borrower's initial public offering of its
equity securities are insufficient to permit the Company to satisfy in full
subsections 3.5.3(i) through 3.5.3(iv), the Net Public Offering Proceeds from
any and all subsequent public offerings of the Borrower's equity securities
shall be applied in the same order and manner taking into account the
application of the Net Public Offering Proceeds from all prior public offerings
of the Borrower's equity securities (i.e., treating all such Net Public Offering
Proceeds as if they were received in connection with a single public offering).

     3.   The definition of "Maturity Date" in Section 12 of the Loan Agreement
is hereby amended by deleting it in its entirety and by adding the following in
its place:

          "Maturity Date" means the earlier of (i) November 24, 2004 and (ii)
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     the first anniversary of the closing date of the initial public offering of
     the Borrower's equity securities.

     4.   Section 12 of the Loan Agreement shall be further amended by inserting
into such Section the following definitions:

          "Harris Indebtedness" means all outstanding principal and accrued
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     unpaid interest thereon payable by the Borrower to Harris Trust and Savings
     Bank pursuant to that Unsecured Note made by the Borrower in favor of
     Harris Trust and Savings Bank on July 16, 1999.

          "Net Public Offering Proceeds" means the proceeds received by the
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     Borrower from any public offering of its equity securities pursuant to an
     effective registration statement under the Securities Act, net of any
     underwriting discounts and commissions and other reasonable and customary
     transactions costs, fees and expenses properly attributable to any such
     offering and payable by the Borrower to non-Affiliates in connection
     therewith.

     5.   Full Force and Effect.  Other than as specifically provided herein,
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the Loan Agreement, as amended hereby, shall remain in full force and effect,
and is hereby ratified and confirmed in all respects.

     6.   Amendment.  As required by Section 11.3 of the Loan Agreement, the
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Borrower and the Lender hereby consent to this Amendment.

     7.   Counterparts.  This Amendment may be executed in separate
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counterparts, each of which is deemed to be an original and all of which taken
together constitute one and the same agreement.

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    IN WITNESS WHEREOF, the parties hereto have executed this Amendment on the
date first written above.

                              ZEFER CORP.

                              By: /s/ James Slamp
                                 ---------------------------------------

                              Its:______________________________________

                              GTCR CAPITAL PARTNERS, L.P.

                              By:   GTCR Mezzanine Partners, L.P.
                              Its:  General Partner

                              By:   GTCR Partners VI, L.P.
                              Its:  General Partner

                              By:   GTCR Golder Rauner, L.L.C.
                              Its:  General Partner

                              By:  /s/ Philip Canfield
                                 ---------------------------------
                              Its:  Principal

              SIGNATURE PAGE TO FIRST AMENDMENT TO LOAN AGREEMENT<PAGE>

                                                                   EXHIBIT 10.55

                   SECOND AMENDMENT TO STOCKHOLDERS AGREEMENT

     This SECOND AMENDMENT TO STOCKHOLDERS AGREEMENT (this "Amendment") is made
this ninth day of February, 2000, by and among ZEFER Corp., a Delaware
corporation (the "Company") and GTCR Fund VI, L.P., a Delaware limited
partnership ("GTCR"). Any capitalized term used in this Amendment which is not
otherwise defined herein shall have the meaning assigned to such term in the
Stockholders Agreement (as defined below).

     WHEREAS, the Company and GTCR are parties to that certain Stockholders
Agreement, dated as of March 23, 1999 (as amended and modified from time to
time), by and among the Company, GTCR and certain other stockholders of the
Company (the "Stockholders Agreement");

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Company and GTCR agree as
follows:

     1.   Section 1(a)(i) of the Stockholders Agreement in hereby amended and
          restated in its entirety to read as follows:

          (i)  the authorized number of directors on the Company's board of
               directors (the "Board") shall be established at nine directors.

     2.   Section 1(a)(ii) of the Stockholders Agreement in hereby amended and
          restated in its entirety to read as follows:

          (ii) the following persons shall be elected to the Board:

               (A)  until the later to occur of (i) such time as GTCR Capital
                    Partners, L.P. ("GTCR Capital") no longer holds any capital
                    stock (or securities exercisable or convertible into capital
                    stock) of the Company and (ii) such time as no Loan
                    Obligation (as defined in Section 12 of the Loan Agreement)
                    is outstanding, two representatives designated by GTCR and
                    one representative designated by GTCR Capital; and
                    thereafter, three representatives designated by GTCR
                    (collectively, and regardless of whether designated by GTCR
                    or GTCR Capital, the "Investor Directors");

               (B)  William Seibel and one additional Executive of the Company
                    designated by the Company's chief executive officer (the
                    "CEO") (each, an "Executive Director" and collectively, the
                    "Executive Directors"); and

               (C)  four representatives chosen jointly by GTCR and the CEO (the
                    "Outside Directors"); provided that no Outside Directors
                    shall be a member of the Company's management or an employee
                    or officer of the Company or its subsidiaries; provided
                    further that if GTCR and the CEO are unable to agree on the
                    Outside Directors within 10 days after the date specified by
                    GTCR for electing the Outside Directors, then GTCR, in its
                    sole discretion, shall designate the Outside Directors;

     3.   Other than as specifically provided herein, the Stockholders
          Agreement, as amended hereby, shall remain in full force and effect,
          and is hereby ratified and confirmed in all respects.

     4.   As required by Section 10 of the Stockholders Agreement, the Company
          and GTCR hereby consent to this Amendment.

     5.   This Amendment may be executed in two or more counterparts, each of
          which shall for all purposes be deemed to be an original and all of
          which shall constitute the same instrument.

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            IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be executed on the day and year first above written.

                                     ZEFER CORP.

                                     By:    /s/ James Slamp
                                           -----------------------------
                                     Its:
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                                     GTCR FUND VI, L.P.

                                     By:   GTCR Partners VI, L.P.
                                     Its:  General Partner

                                     By:   GTCR Golder Rauner, LLC
                                     Its:  General Partner

                                     By:    /s/ Philip Canfield
                                        -----------------------------
                                     Its:  Principal

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