Z Tube + K&N Drop in Filter + Rev up airbox= Best intake ever.
Headers: Too hard to get too and not gonna see any power gains
Exhaust: Catback with HFC's
Motordyne 5/16 Plenum spacer
Osiris tune
Easily 30-40 WHP maybe even more

 

With mrev plenum, plenum spacer, high flow cat-backs, and osiris, the dyno tune yielded 290 whp on my 05 coupe.