I'm not a huge fan of the GReddy Evo (the muffler's just so...big) but at least it's not too loud. The N1 on the other hand, is way too loud just like every other canister style exhaust.

If you just HAVE to get a new exhaust then I'd go with either a GReddy SP2, RS*R Exmag or Tanabe Super Hyper Medalion.