Well I Have a system he might like. Like cobb said the Pioneer DEH-P7400MP head unit is really good an has a TON of different functions that you can play with to make your audio quality better. As for an amp, I have a 2 Channel Lanzar Vibe 250 1000wt amp. It pushed my sub perfectly with the upmost quality and never had any problems with it. Subs..I have one JL Audio 12W3 in a H.O.B.P. box. I have had people come over to my car and ask me if I had 4 12s. The box makes the system. BTW: the H.O.B.P. box comes with the 12W3 already in it so you don't have to buy the sub and box separate and then put 12 in.

Prices:
head unit~$250-$300
amp~$175-$200
sub/box set~$350-$400

~Green Civic EX