Originally Posted by pbonsalb
If you don't want to change the software to accomodate catless running, then you should stick with a pipe that eliminates just one set of cats or that substitutes high flow cats for the one set that remains. No CEL, emissions passability, substantial power gains, and closer to the ability of the stock ECU to adapt to take advantage of the improved flow. You can find dynos for these kinds of x pipes with some searching. Fabspeed makes one, Sosi makes one, Turner sells cat delete pipes for the stock exhaust, AA and Challenge and Akrapovic and others sell complete pipes with high flow cats, etc.
I hold one of the higher whp charts at 407.7whp along with jonmartin at 407whp and we used modified stock x pipes. My car even hadPeople can preach all they want about x designs and pipe diameter but ive yet to see it translate on the dyno sheet.
Ive since put on a full gintani true dual x pipe but that is for the great exotic sound more then the performance.