Hello and welcome to CEG!
To answer your questions. The front and rear doors on the Contour are 6x8/6x9 (depending on the manufacturer). Pioneer makes some 6x8's that are a perfect fit in our cars, although I'm sure the guru's will reccomend a cheaper likely better sounding solution.
You can pretty much pick up any brand name deck in the same price range and they will sound the same. I have a Pioneer DEH-P7400MP in mine and I love it. Plays MP3s and has a cool lookin LCD display. It also has a built in 50x4 watt max amp (around 20x4wrms).
www.sounddomain.com has them for $229 + shipping, retail is over $300 if you buy it in any store.
