well, when i spoke with a rep for HP (when they were answerin the phone for me) he said i needed (strongly suggested) to change my mufflers for unchambered mufflers to help the turbos spool quicker since they are a lil too big for my car. I have Flowmaster 40's or 50's on it right now. Does anyone know of a nice sounding unchambered muffler? i have access to an almost new set of Bullets at my mechanics shop. i heard them on a fox body and it was quiet in the cabin. I'd rather like a raspy or maybe more agressive sound from my stang. i know the turbos will muffle the car, but i want it to have a good, mean sound. it does have an x-pipe on it, catless.