My car has 1' 3/4 headers, 3 in exhaust all B&B no cats, VEC 1, 70 mm TB's 1.7 T&Ds, and 3:45 gears. This run was with a 28 in. tall slick which I think was a little to much may change gears to 3:73 or get 26 in slicks. But all in all the car feels and runs great just a little tweaking and shall be running a couple few tenths quicker. As my partner 9D9LS1 stated Sean has engineered a great product the fit and finish the tight tolerences all necessary hardware to install, along with cioncise instructions and very personal service from Sean himself. A tremendous amount of time and hard work has gone into this S/C unit and it shows, a very remarkable piece. Thanks Sean.