I'm dead honest, screw the rears. It is absolutely unnecessary. If you get the front speakers running as loud as you like, the rears will add nothing (without any type of sound processing).
Another important thing, check the depth you are working with. If they are in the doors, more than likely the window or window track may hinder the depth of the speaker you can mount. I honestly wouldn't consider any speaker before knowing the depth. 6x9's can get pretty deep. This isn't a problem in most cases, as most are mounted in rear decks of cars.
Find out the depth, and I'd be more than happy to help you find a good set.