Welcome, defintiely! No doubt the more you read from this site, the more ideas you'll have. Your intake and exhaust depend on your future goals - do you eventually want a supercharger or a turbo set-up? If so, then the intake will get replaced so don't spend too much money on it.
If not, there are a bunch of options out there. I also have the stillen intake, but swapped out the Stillen Z-tube for a Spectre chrome tube. This changed the placement of the Stillen heat shield, so I had to make a quick little custom bracket to hold it in the right place. You COULD spend 250 on an intake kit, but if you have any experience under the hood, you could do it a lot cheaper if you just buy the parts individually from eBay and/or some local auto shops.
There are also a lot of options for exhaust out there - again depending on your future plans. I have the Stillen exhaust which I absolutely love, but some people say it's too expensive. The NISMO exhaust is also very popular as well as the HKS legamax.
My intake, plenum spacer and exhaust added 21whp according to my dyno numbers. The intake and exhaust also slightly improved my gas mileage, as long as I'm not agressive...