Hi, my d16y8 is pretty much stock. All I have into it is the basics, a short ram K&N Intake, DC Sports Header, 2.5" Cat-Back exhaust, Stage 1 Exedy Racing Clutch, and a Lightweight Fidanza 7lb Flywheel. Will adding a bigger throttle body and a racing intake manifold make a difference? If so, will it be mandatory to tune the car then...

 

I "think" you would see a better performance gain from a camshaft upgrade than a IM/TB.

 

Or upgrade to a B, H, or K Series...