with the hpp handling package, you have the magneride suspension, theyre awesome, and i wouldnt change. just run it in track mode. you may want to do some homework on the ford performance magneride bundle that includes a new calibration for magneride. the kit comes with sway bars, springs, and a software update. not sure how the sway bars and spring rates compare to the stock hpp handling package. no experience with autocross, but for fun in the mountains i really enjoyed moving from 19x9 to 19x10s, and upgrading the front brakes to the brembos from the GT.