http://www.crutchfield.com/S-5zotibk...0&I=107MMC6500

http://www.crutchfield.com/S-5zotibk...00&I=108perf61

http://carstereo.pricegrabber.com/se...sterid=1137070


Any opinions on those?

How about staying local with AVI Sound. They have some very good component sets in the price range you are looking at. AVI Sound

i built those this summer, and those ones didnt turn out as nice as i wanted. built a cuople of sets after thet using mb quart rce 216s, they looked and sounded awesome. lots of bass, and they imaged their asses off. pm me and ill send you pics.i could build some 4 you and ship them. very strong and only weighed a couple of pounds [img]graemlins/thumb.gif[/img]

by the way ...quart also make an "add a woofer system" that is very nice.the model# is rce 216, and comes complete with a crossover system thatmakes it perfect for your application. they would hook up in parralel with your current front speakers. if i were you though...i would diconnect the 4s and go to a good component set in the doors :D