I've noticed this since I got on my GT for the first time which is around 8 months ago. The thing that I"m curious about is how come when I take off sometimes in 1st, the car felt like it doesn't want to go? I can floor it and the RPM will just rise and the car doesn't want to go. It still does the same thing since I got my exhaust done but I rarely felt it. It accelerate just fine most of the time however.. I'm sure that this has been asked before, but still I want to know what caused this. Is it normal? Thanks