Finally my car sounds like music with Borla and LT's. The only change I did was installing a single 3" high flow cat after the Y-pipe. I don't know how it will hurt my performance, I dynoed 386 rwhp and 391 tq last week, but I believe that having cuttout fully open shouldn't be to bad. No more high pitch exhaust sound, popping, and my exhaust has a deeper sound, just the way it should be