Since my last post:
New engine mounts from an e24 635i, new transmission mounts from an auto e21. Both beefier rubber but approx same dimensions.
New rotors, EBC redstuff pads. Big improvement.
New exhaust from downpipes. e46 M3 midsection and Audi S5 rear muffler.
Overall the new exhaust has improved drivability a lot - solved some funky vibrations due to the large stock midsection touching the driveshaft hoops, plus the removal of the restriction of a stock 2.5L M20 exhaust seems to have improved the pickup somewhat (obviously speaking subjectively). Unfortunately a nasty resonance about 2k RPM, but have a much larger Magnaflow dual>dual coming from the US which will hopefully help.
Love the new tips though.