i would go with 12's. they seem to be the best all around sound. and as for the brand JL AUDIO. they make some of the best subs.and they are built to last.i had 3 12w6 's in my escort they were awesome.
there are a few suppliers on ebay that are almost half the price as any store. jl also makes a good amp. i prefer US AMPS .i had an old school 400 that i abused and never had a problem.it was not supposed to be run a 1 ohm but it kept on going for 5 years. after which i sold it and it could still be going. also a sealed enclosure is the way to go. shawn