Well I don't have standalone (yet) but I consider my car well tuned. Fuel curve is dam near perfect. Anyway back to the topic I would go custom on everything. Treat your car to the best parts...little more money but you get to pick and choose your parts. Good luck with whatever route you take and let us know how it goes or if you need any help. I would suggest doing some research on every part before just taking someone's word for it and buying it just because they say its good.