Just put in Bimerworld poly (but not bolt-through) transmission mounts with enforcer cups. Surprisingly no (or barely noticeable) extra vibration at idle. However, with car in gear there is definitely noticeable extra vibration from roughly 1000-2000RPM, or maybe it's from 1500-2500 RPM. Just drove it from the shop to work, so will drive it for a few days and see if it changes and whether it becomes annoying on long drives. This is with stock motor mounts that are 18 months (and 15,000 miles) old. Now glad I didn't go for bolt-through poly transmission mounts, since this car is 90% street, 10% track.
Previously had UUC black tranny mounts without enforcer cups. They had slightly more vibration than stock, but less than the Bimmerworld mounts (with enforcer cups). I'm guessing the Rogue Engineering transmission mounts would feel similar to the UUC back mounts, though I haven't tried the RE ones.
Lowering my car's resale value one track day at a time...
Last edited by LivesNearCostco; 11-02-2011 at 06:08 PM.
Reason: added more commentary