I got a 2010 WRX with the non-premium 4-seaker stereo system. The dealer did a free Subaru sub/amp installation. It sucks majorly. Can't even tell from the sound if the sub is there or not. Anyway, can't look a free horse in the teeth...

So, I am planning to upgrade the stereo. I am planning on replacing the stereo unit and the 4 speakers with an Alpine or similar system. I am not a DIY guy, so I am looking at Best Buy or something like that. Any recommendations? Also, will the Subaru sub perform any better with a better stereo system?