Howdy, bf,

The e34 m5 solid upper control arm bushings are probably longer lasting than the 750 bushings.
A few of us, on this board, have gone to the even larger 850 brakes, at almost 13" rotors. If I remember, the 750 rotors (used with the e28 m5 front rotors) were the same diameter as the e34 535 front brake rotor.
I have a 15 pound e28 flywheel in my 535. It is a definite upgrade & quiet.
The z3 shifter is rubbish in the e34. The geometry is off, & the plastic ball wears out quickly.