<PAGE>   1
EXHIBIT 2.4


                                 PROMISSORY NOTE


$1,500,000                                                         July 31, 1999

         On July 31, 1999, for value received,  the undersigned  promises to pay
to the  order of  BINGHAM  FINANCIAL  SERVICES  CORPORATION  ("Bingham") at its
offices located at 260 East Brown Street, Suite 200, Birmingham, Michigan 48009
the sum of ONE MILLION FIVE HUNDRED THOUSAND AND NO/100 DOLLARS ($1,500,000.00)
with  interest from the date of this Note at a per annum rate equal to the prime
rate of Comerica Bank  ("Bank") from time to time in effect plus three  quarters
of one percent  (0.75%) per annum until  maturity, whether by  acceleration  or
otherwise,  or until an Event of Default,  as defined below, and after that at a
default rate equal to the rate of interest otherwise  prevailing under this Note
plus 3% per annum (but in no event in excess of the maximum  rate  permitted  by
law).  The Bank's  "prime rate" is that annual rate of interest so designated by
the Bank and  which is  changed by the Bank from  time to time.  Interest  rate
changes will be  effective for  interest  computation  purposes as and when the
Bank's prime rate changes. Interest shall be calculated for the actual number of
days the principal  is  outstanding  on the  basis of a 360-day  year.  Accrued
interest  on this Note shall be payable on the  Maturity  Date when all amounts
outstanding under this Note shall be due and payable in full.

         The initial  indebtedness  ("Loan")  evidenced by this Note and any and
all  modifications,  renewals or extensions of it,  however  evidenced, and all
costs of  collecting  same  ("Liabilities")  are secured by those assets of the
undersigned  described  in a certain  Pledge  Agreement  of even date  ("Pledge
Agreement")  and by all  property  of the  undersigned  from time to time in the
possession  of  Bingham   (collectively   "Collateral"). The  Liabilities  are
guaranteed by Detroit  Mortgage and Realty Company ("Guarantor")  pursuant to a
Guaranty of even date ("Guaranty").

         If the undersigned or Guarantor (a) fails to pay any of the Liabilities
when due, by maturity,  acceleration  or otherwise;  or (b) fails to comply with
any of the terms or  provisions  of any  agreement  between the undersigned  or
Guarantor and Bingham; or (c) becomes insolvent or the subject of a voluntary or
involuntary  proceeding  in  bankruptcy,  or a reorganization,  arrangement  or
creditor composition proceeding, ceases doing business as a going concern, or is
the subject of a dissolution, merger or consolidation; or (d) if any warranty or
representation  made by the undersigned in connection  with this Note or any of
the  Liabilities  shall be discovered to be untrue or incomplete in any material
respect;  or (e) if there is any  termination,  notice of termination,  material
breach or Event of Default of or under the Guaranty or the Pledge Agreement;  or
(f) if there is any material failure by the undersigned or Guarantor to pay when
due any of its other indebtedness (other than to Bingham or Comerica Bank) or in
the observance or performance of any material term, covenant or condition in any
document  evidencing,  securing  or  relating  to such  indebtedness;  or (g) if
Bingham  reasonably deems itself insecure believing that the prospect of payment
of this Note or any of the Liabilities is impaired or shall fear deterioration,
removal or waste of any assets of the undersigned or Guarantor; or (h) if there
is filed or issued a levy or writ of  attachment  or garnishment  or other like
judicial process upon the Collateral,  then Bingham,  upon the occurrence of any
of these  events  (each an "Event of Default"),  may at its option and  without
prior notice to the  undersigned, declare

<PAGE>   2


any or all of the Liabilities to be immediately due and payable (notwithstanding
any provisions contained  in the evidence of it to the  contrary), sell or
liquidate all or any portion of the Collateral, set off against the Liabilities
any amounts owing by Bingham to the undersigned, charge interest at the default
rate provided in this Note and exercise  any one or more of the rights and
remedies granted to Bingham by any agreement with the undersigned or given to it
under applicable law. All payments under this Note shall be in immediately
available United States funds, without setoff or counterclaim.

     This Note shall bind the undersigned, and the undersigned's successors and
assigns. The undersigned waives presentment, demand, protest, notice of
dishonor, notice of demand or intent to demand, notice of acceleration or intent
to accelerate, and all other notices, and agrees that no extension or indulgence
to the undersigned or release, substitution or nonenforcement of any security,
or release or substitution of the undersigned or Guarantor, whether with or
without notice, shall affect the obligations of the undersigned. The undersigned
waives all defenses or right to discharge available under Section 3-606 of the
Uniform Commercial Code and waives all other suretyship defenses or right to
discharge. The undersigned agrees that Bingham has the right to sell or assign
any interest in the Liabilities, and that, in connection with this right, but
without limiting its ability to make other disclosures to the full extent
allowable, Bingham may disclose all documents and information which Bingham now
or later has relating to the undersigned or the Liabilities.

     To induce Bingham to extend the Loan evidenced by this Note, the
undersigned agrees to reimburse Bingham for reasonable legal fees and expenses,
not to exceed $35,000, incurred by Bingham in connection with the negotiation
and drafting of the documents contemplated by both the Loan and the H&W
Reorganization Agreement, as defined in the Pledge Agreement.

     In addition, the undersigned agrees to reimburse Bingham, the holder or
owner of this Note for any and all costs and expenses (including without limit,
court costs, legal expenses and reasonable  attorney fees, whether or not the
suit is instituted and, if suit is instituted, whether at the trial court level,
appellate level, in a bankruptcy or administrative proceeding or otherwise)
incurred in collecting or attempting to collect this Note or incurred in any
other matter or proceeding relating to this Note.

      The undersigned acknowledges and agrees  that there are no contrary
agreements, oral or written, establishing a term of this Note and agrees that
the terms and conditions of this Note may not be amended, waived or modified
except in a writing signed by an officer of Bingham expressly stating that the
writing constitutes an amendment, waiver or  modification of the terms of this
Note. If any provision of this Note is unenforceable  in whole or part for any
reason, the remaining provisions shall continue to be effective. THIS NOTE SHALL
BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF
MICHIGAN.

         THE MAXIMUM INTEREST RATE SHALL NOT EXCEED 25%, OR THE HIGHEST
APPLICABLE USURY CEILING,WHICHEVER IS LESS.

         THE UNDERSIGNED AND BINGHAM ACKNOWLEDGE THAT THE RIGHT TO TRIAL BY JURY
IS A CONSTITUTIONAL ONE, BUT THAT IT MAY BE WAIVED. EACH PARTY, AFTER CONSULTING
(OR HAVING HAD THE


<PAGE>   3



OPPORTUNITY TO CONSULT) WITH COUNSEL OF THEIR CHOICE, KNOWINGLY AND VOLUNTARILY,
AND FOR THEIR MUTUAL BENEFIT, WAIVES ANY RIGHT TO TRIAL BY JURY IN THE EVENT OF
LITIGATION REGARDING THE PERFORMANCE OR ENFORCEMENT OF, OR IN ANY WAY RELATED
TO, THIS NOTE OR THE LIABILITIES.

                                       DMR FINANCIAL SERVICES, INC.
                                       a Michigan corporation

                                       By:  /s/ Mark C. Stevens
                                            ------------------------------------

                                       Its: President and CEO
                                            ------------------------------------