Well, i suggest buying a muffler (Flowmaster, Gibson, dynamax etc..) and getting a custom install at a local muffler shop. It will be cheaper in the long run and you have more control of what you get.
I went with a flowmaster 40 series and i got good results
as for the intakes, K&N makes a good kit along with volant, there are also some folks on here with DIY (Do It Yourself) intakes and have had good results. Personally i would go with K&N, they have a good history with intakes.