More of both is better :). For the difference you will see it isn't going to give you a huge gain or hurt you either. The sound will make it feel like 15 more hp anyway.

I would say you would be very lucky to get anywhere near 10 hp from and entire exhaust system alone. I checked into an exhaust, intake and CAI upgrade, with tune, and found some data on a car similar to mine, and the hp gains from the whole package was 31 to the rear wheels.

that would cost over 1 thousand I think

Absolutely....the intake is close to $500, and the CAI with the tuner is almost $700, not to mention the headers/exhaust. I actually thought 31HP was kind of low for the amount it costs, but I guess not bad.

I was thinking like you (dangerous I know lol) and still think it's a little high for the return

Yeah that is dangerous.:lol But it does seem to take alot of $ to get HP. With these upgrades I mentioned, depending on brand, you're looking at spending about $65-$70 for every 1 HP gain.(to the wheels of course). Now compare that to a supercharger. Yeah you're paying a lot more for that upgrade, like about $7000 for a good Ford Racing, or Kenne Bell, but according to every Dyno test I've seen you're gaining about 250+ hp to the wheels, on this coyote engine anyhow. So that works out to about $25-$30 for every 1 HP gain. I know it seems like huge money, but it's also huge gains, for less than half the $/hp.:tup

I feel bad for the guys that do not have a plan as they tend to start over and over wasting big money