Hello and welcome! Nice RSX as well.
If he wants to boost, I wouldn't spend the money on the intake and possibly not even the exhaust.
There is a Stillen supercharger prep thread, where they say the (currently best CAI) Stillen G3 doesn't fit.
And for the exhaust, if you want to supercharge it a 2.5" woudl be fine.
But if you want to put a turbo on you're better of with a 3", so you would have to replace it again...
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