I dynoed right after an 01 GT with a bullit intake and similar mods...bassani x-pipe, weld in flows, CAI. He pulled 242 peak horsepower. My results are in my signature. Again, that's peak horsepower and I don't know how much higher his average horsepower was. On a basically stock mustang I suspect there wouldn't be much in the way of power increases, but if you plan on porting and doing work on the motor, my guess is that you'd see a bigger horespower and torque increase for every mod down the line. You may change your mind on the supercharger/nitrous/turbo mod down the line. I'd planned on staying NA, but am now saving for the Kenne Bell kit. If I went w/ any other power adder, I'd use the bullit intake as the plastic stock seems pretty crappy.