[KirkEvil]

Kind of an old thread, but I would just go with the LPP stainless Y if you havent decided yet. As mentioned, you will not see a loss of performance from the flat spots unless you are making ridiculous power. Those flat spots will also keep the Y pipe from banging the floor over bumps and acceleration.

FYI, I tried running a tsp catted Y without the flat spots and it sat right against the under body. The banging and vibration was a real PITA, which led me to buy an ORY with the flat spots.