i dunno about the e34 m5 but my car is a 89 525 euro and i had the standard seat with no lether only velour and manual seat..I found a beige electric one in the yard that came from a 94 525. i swapt it in and its a perfect fit no modifications whatsoever and as for the wirings of the electric seats, the wiring harness are there its just under the carpet hidden under where the seat will be placed...hope this helps![]()