I put a Stillen exaust on my 91 SE-R a couple of years ago. It is very unplesant under some conditions. There is a loud resonance under heavy acceleration, much too loud. I called stillen to return the exaust and they refused. There attitude was essentially live with it. I added extra padding (foam carpet pad) in the trunk and under the rear seat and deck lid. I added extra rubber exaust dounuts, wedged rubber pads under the heat shields and put epoxy wedges in the bell shaped exaust tip. This afforded little improvement. Many a passenger has commented on the noise, it is bad. Needless to say Stillen will get no more of my business.