Help me pick an amp and a sub

My car is a 92 Civic CX hatchback. What I have so far is a Nakamichi CD-500 head unit, and CDT component speakers. I need an amp now.. and I guess I need a subwoofer.

Help me choose the right setup. I'm willing to pay up to $250-300 for each of them if necessary, but saving money is good.

I'm just looking for the best sound quality. Loudness doesn't matter to me.. I just want it to sound really good. :)

I was thinking about an Eclipse amplifier and sub.. but I want to hear some suggestions.