I have a similiar problem (scrunching brakes at slow speed) with my 93 300 TE. It is worse in the winter and better in the summer. My mechanic believes this is because newer brake pads are made out of new materials (including pieces of metal) which wear differently and have different friction coefficients; this confuses the computer. His advice was to brake very hard from 50-60 mph down to zero every so often to smooth out the brake pads. Using this technique we have been able to manage (not eliminate) this problem.
Regards,
Steve