If you go CAI, I'd 2nd this. ^^^^^Get a Hybrid Racing 3.5" CAI. Silicone beats metal intake tubing all day long. Lower IAT's.
Of course you'll need a MAP tune with it. Add a header and you'll be around 220whp depending on the dyno, but you'll feel the difference, especially passing all those 300 hp luxury sport coupes.
What header would I make more power that isn't too loud? I believe the skunk2 alpha will be too loud since I'm CaliforniaI have a Skunk2 CAI and I don't recall having to cut anything. Install was actually quite easy but as with any of the larger Chai's a tune would be required.
As for a header, are you thinking a shorty to allow you to still run a catalytic converter? If not, most guys here run the Skunk2 Alpha Series from what I have found. There is also K-tuned, Invidia, PLM, etc.