I'm at wits end with trying to subdue the interior noise/vibration from my 245's stock exhaust. I know 240s are noisy, but this is silly. I checked all the rubber mounts. I cut off the heat shields (the welds were broke). I even bolted a heavy bar from the M47's rear housing and welded it to the pipe, and welded a plate on the head pipes to tie them together. I installed new motor and tranny mounts. This all helped firm it up a good bit, but still the vibration, especially at lugging rpms. My next move might be replacement of the exhaust with one of the high flow types (IPD or similar). Anybody tell me if this will help - mind you that I'm not as concerned with noise levels going out the end of the tailpipe as I am about the vibration/booming noise in the cabin. Ideas?