The size of injector recommended will depend on the boost levels you run, but On3 recommends a minimum of a 47lb injector with this kit. At regular boost, 47lb injectors and a blow through digital mass air meter will be required for tuning purposes. The factory fuel pump will support up to 500rwhp without adding a BAP. If you go past those numbers, a BAP will be required for tuning purposes to ensure you are getting enough fuel. With this specific kit, the downpipes stop at the factory midpipe location, so you can bolt your factory, or any aftermarket midpipe intended for factory headers back up to it and you are good to go.