Mine was an easy mod, but I use the 90mm Q45 with the q45 TPS, I'm at 500 RW with an auto, and I didnt want to upgrade again later.
I may be crazy, and I cant back it up with proof, but when I changed to 3" pipe, 12x24x4 I/C, Q45, And Ron R shorty, I feel the response is much better off idle...