Invidia makes a great exhaust. I have the Q300 on my STi, and also had the Q300 on my last wrx. In my opinion the Q300 mated with an aftermarket downpipe is the perfect volume of noise. It really all depends on you. If you want more of an obnoxious boy racer style exhaust then go with the N1. The thing that I hate about the N1 are the two huge angled fart cans. The Q300 looks relatively stock with just larger tips.
Too each their own. Get what you like. But you can't go wrong with invidia exhausts.