Plenum, induction kit, hi flow cats or decats, exhaust. But even on a standard car some power will be found, it will be better on fuel and will have better drivabilty. TBH its about what you want and the Uprev reflash will make the best of what you have. I think anyway.
I wouldn't bother with an induction kit personally. Stick with the standard induction and get a free flowing panel filter for it. Most, if not all induction kits will lose you a few bhp.