Welcome.
Search this site for all the info on the Gen 3's you could possibly imagine. It's been covered from just about every angle.
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The Gen 3's are proven to pick up gains. I suggest looking at the Parts For Sale section to pick up a used set to save a few bucks....that, or wait until November when Stillen has their black friday sale. FYI, the filters require cleaning every 30k miles or so, which is about 3 years.
As far as exhaust, those are all good choices and really comes down to the sound you want. Fast Intentions is a popular choice, but be prepared to wait your turn in line.