If the car is a type-s start with race header and then get a Hondata #4 reflash. If you put a header in look into the Hondata intake gasket, it lowers heat therefore giving you 3-5 hp to the wheels. The header will give you about 5hp the hondata reflash will give you around 10-13hp. Lets say you have a type-s withproven after market parts. Injen cold air intake, Magnaflow exaust, Spoon race header, Hondata reflash#4 and Hondata gasket. You will dyno around 210whp. If you get your car tunned after the mods you should be around 212/218 whp and your torque will be about 20 higher. This might not seem like much but when a stock 350z is putting out 230-240 whp, our little RSX type s can keep up if not beat the 350Z... STOCK!!! Hold off on things like pulleys and lighter flywheel for the next big upgrade. when you save 1500 upgrade the flywheel, clutch,clutchplate, pulleys... Stick to bolt ons, Turbos and superchargers are more headach, plus your engine life gets cut down to half, unless you have alot of money to put into new cam, lifters, pistons, valve train...ect. Ohhh that reminds me, when you reflash your car your rpms now go up 2 8500, stock is 8100, v-tech kicks in at 5200 and more torque at 3000-4000rpm, car pulls in 5th gear now, no need to down shift to pass people on the freeway. Anyway if you like to run your car in the 8500s, you better upgrade the valve train next. (NEXT UPGRADE AFTER header/reflash)stock valves can handle the higher rpm, but why take the risk. good luck