I am thinking about taking the back speakers out and replacing them with custom fiberglass enclosures that will hold a pair of JL 6w0s (or 8s if I can get them to fit, doubtful). I am going to put a pair of alpine SPx-177as up front. As far as amps, probably a mono class D for the subs (mid level brand line alpine or something) and a nice 2 channel for the comps.
I haven't decided on the head unit, I like the idea of keeping that stock as to not draw attention to it. It depends on how much signal loss I have going through a line level converter.
If you don't mind loosing trunk space I would put a 10 or 12 in the back. Personally I want to keep the trunk space.
If you are going for SPL, my solution wouldn't be for you. I am more into SQ and I don't listen to much rap (and no hip hop).