06 WRX wheels and 06 STI wheels have different lug patterns. Don't know why, doesn't make sense.
06 STI - 5x114.306 WRX - 5x100
So to answer your original question. No, an 06 WRX wheel will not fit on your car, without a stud adapter.
Heres a wheel guidehttp://
www.subydude.com/parts/...1.php