On an 01 cobra with supporting mods, an intercooled P1SC with a 3.9" pulley, you should see roughly 425 rwhp. This is just about your glass ceiling unless you plan on building the motor. (The rule of thumb is to stay below 450 whp on a stock bottom end. Some guys have surpassed this mark with no problems while others have blown motors with less.) You can buy a new kit or used. I found my used one on SVTPerformance, like mentioned, but wished I would have bought new. The 03/04 Mach 1 kit will work also, you will just have to buy a new mounting bracket. I procharged my 99 a few years ago. If you have any questions, feel free to ask.