Hate to be captain obvious and i know i don't come around these parts much but i gotta say, 400-450whp is a bit much for a dd. I suspect you've never ridden in anything worth more than 250whp so while it's cool to speculate about how awesome it would be to own a 400-450whp daily driven car, it's completely and utterly non-realistic. Buy a stock wrx and you'll be absolutely elated. Then mod it as you deem fit.
Unless I'm totally wrong, and you really aren't a 17 year old kid lusting after some dyno queen of a car which you'll probably wrap around a tree in a street race against a civic dx with an AEM cai and an OBX muffler, get a mustang or camaro if you must have the hp and leave the sporty awd stuff to us.