It is spark and fuel. Get these things right and keep the boost at a reasonalble level and your engine will be fine. You should be fine at 5-8 lbs of boost 7-8 if you can get the charge air cooled down. This is one reason I like the rear mount turbo as it is easier to keep the charge air cool. Our stock exhaust system while not all that great is well suited for a rear mount turbo.