Personally I don't think the airaid is all that great as it uses a lot of the stock parts. I'd recommend a FIPK or Volant.

Exhaust wise all the cat-backs work pretty good, but the cheaper option is to just go to a shop and have them install a muffler (flowmaster, borla, gibson - whatever you'd like). I'd also recommend having the stock piping replaced with 2.5" pipe so it can flow a bit better - my Gibson has 2.5" piping and I've not noticed any drop in low-end torque.

The combo of an intake and exhaust does make some power difference, but don't expect too much or you may be dissappointed. Also don't expect any mpg gains.

It sounds a lot better than stock, though.