well, after a long, LONG wait, i have my mx6 back from the shop with a centerforce stage one clutch, a borla cat-back, and a random tech cat. unfortunately, due to the "450-500 mile break in period" on my clutch, i can't really open it up. but even with how i have to drive now, the mods help. my exhaust (in addition to sounding a lot better) seems like it gave me a pretty decent gain. i also heard something like after the exhaust is worn in a little bit, it sounds even better.