I just replaced both engine mount on my 1.8T with new compatible mounts from a V6 (recommended as a mild upgrade and supplied by Pure Motorsports). Both mounts were shot, leaked purple stuff - the rubber on the driver's side was permanently compressed. The install went pretty smoothly - no concerns after starting engine up and re-aligning snub mount bracket at idle (using the aftermarket APR snub). Things looked and felt good at idle compared to before the fix - much less shake and vibration at idle noticed in the driver's seat. When tightening the mounts and snub mount bracket up I observed the whole block shaking/rocking at idle, but isolated from the frame by the mounts, so all seems good. So after buttoning everything else up I take it for a ride and as soon as I leave the driveway I know it's not good. Major vibration in the cabin from 2K-4K RPM - really no better, or maybe even a little worse from before with the bad mounts. On reinspection after returning to the driveway, I notice the whole exhaust system leading back from about the transmission shaking pretty bad at idle. Again - inside the car all seems good at idle, but I'm surprised how much the block and whole transmission and exhaust system are shaking. I briefly inspected the transmission mount but tough to tell much - the rubber is there and I don't hear any metal to metal noise, but boy is there a lot of movement at that point.

Any ideas what is going on here? My next thought is to replace the transmission mount - maybe it is shot from age (96K miles) and the stress from running with the bad engine mounts. Just sitting and revving the engine causes enough vibration in the cabin to make the whole interior buzz and rattle - it's pretty unbearable. I also thought of removing the snub mount just to see if that is a factor or not. Anything else I'm missing?