After lurking the sites for several years, finally took the plunge and bought an IP 06' 6mt. coupe. Contacted Jason at Riverside and odered a 5/16 plenum spacer, a non rev-up collector and a stock z-tube. After having read numerous threads throughout the years about the minimal hp gains of aftermarket exhausts, I'm sure I'll keep my car stock in that department. Have any of you guys experienced any true hp gains by adding a y-pipe? Anyone dynoed their coupes after adding similar mods? In the next week I'll be adding a clear bra, tints and replacing stock speakers with Boston Acoustics. As you can see I'll be in no hurry to add anything else other than a Tanabe y-pipe maybe. Thanks for any advise.

 

I gained about 9 hp from my XO2. If you would have bought an 07-08 Z with the HR motor, you would get dirty gains from an exhaust.