SLP's LM! Catback
 

I'm experiecing alot of vibration since having the LM1 Catback installed. I s this normal, or is it a bad install? I have a 1999 Z28 A4.

Your exhaust is most likely contacting the body at some point. Put it on jackstands and get under there to find out exactly where its contacting. Make sure you check the driveshaft too, I know mine was pretty close. Once you find out where it is contacting you can undo a few clamps and get that thing straightened out.