Aftermarket Intakes with Stock Exhaust?
 

Hi i was wondering if i would gain or lose power if i put an aftermarket intake like the Stillen Gen3 or others can someone please help?

No. Keep in mind that the ECU will try to adjust on it's own and that is hard to predict what it ultimately wants to do. There is more than enough info here to answer your question. I'd buy a CBE first anyways. Gains aren't relegated to top end and you get a killer soundtrack to boot.