I just got a pair of Polk EX-693a's real cheap at circuit city. They dropped right into the back of a 94 White With Wood (WWW) Roadie Wagon. It was so easy the guy even remounted the remote opener receiver while he had the panels out. Took a while to reset the bass, treble, and fade (the arlington speakers said 10 Ohms!) but I'm happy with the upgrade. Sounddomain.com has the best prices I've seen, if you know what you want. Just ordered an Alpine MRV-F357 5 channel amp from them. Now to find a pair of fronts and a good clean sub... . It's a good time to buy as last years stuff is going CHEAP!
I let the guys at circuit city install the rear speakers, but I think I'm going to be on my own for the rest, as they "only do factory replacements" and I'm looking to put at least 5.25's in the front.