The SCT pipe works well flow is no problem, turbo spikes fast, part of the reason I went 3" is for future plans for the car larger turbo and such so it can handle more. The front pipe has the high flow race cat and the only problem I had to solve was a 4-4-3 code for TWC efficiency, this code sent the ecm a message to limit the boost to 5pounds HOW RUDE! The problem was that the O2 sensor holes were side by side, the second sensor that tells the ecm that the cat is working by coparing the front sensor reading to the rear one. Side by side that does not work on my year. The fix was to make a new hole in the proper spot, all is good now. A C70 in town had the smae system put on his car no sensor problems that I herd about. Oh well she works well now, the pic on my site shows the diff.