i'd go with CDT's from my personal experience... if you can handle installing a set of 3 way components, that's all you'll need, running rears would just take away from the front setup.
thezeb.com has the CL-641's on sale for $250 which is a crazy good deal (
http://www.thezeb.com/detail.aspx?ID=1085 ) i got these in my car and they absolutely crank and are full of bass, enough to make my hanging air freshener do some dancing :P for that price i don't think anything can compare, but of course installing 6.5" drivers, 4" midranges and tweets, and 2 crossovers per side can be quite the task, but will definately pay off in the long run...