I just got a Invidia Q300 cat back. For me it is perfect. It's quiet and sounds very good. I honestly did not feel any HP difference but I'm use to more substantial changes lol.

I ordered a Stillen G3 intake today for it. They seem to pick up a noticeable difference over 6500 rpm making 15whp more after 6500. 15whp is not a lot but in a all motor car it is pretty substantial increase.

Resonated test pipe is next. I'm in Florida so i don't plan on spending the extra amount for a high flow cat when we don't have emissions laws.