ive had my 88 GTU for almost 3 years now, and ive done alot of work to it. full racing beat exhaust (header, pre-silencers, mufflers), K&N intake, turbo flywheel, turbo trany, turbo driveshaft, turbo diff, turbo rear axles, ACT stage 2 4-puck clutch, ACT heavy duty pressure plate. the car is gutted and has had the smog pump removed, the power stearing pump removed, and the A/C removed.

the car has been running great except the diff mount was broken (thunk) so i replaced it with a Polyurithane one and at the same time put in polyurithane trany mounts. then the thunk turned into a kind of buzz under slight acceleration, and progresses to a vibration under heavy acceleration.

I figure it has to be something with the diff mount but i cant figure it out. any ideas?