If you want a nice system for you car. You have to get rid of that stock radio. I agree it looks nice but it old and out dated. Anyway All the new high end cars have TV, DVD, NAV, ECT. So I went with a Double Din 7'' inch screen TV, DVD, NAV, mp4, Sd, ect. I think it looks nice. I've look at a few 98's and they had a Nav, and DVD as an otp. So to the few people who rode in my car thinks my car came for the dealer with that set up already. Second you can add more bass with out being too loud. I would take out the stock sub and replace it with a PIONEER
TS-SW2541D. It's an 10'' inch sub and it's a Shallow Mount sub so it won't take up much space at all. You also can put the new sub in place of the stock sub if you cut the mental dash to a larger size. It doesn't take much to make this type sub fit in the rear dash. And you don't need a very powerful amp to play it. If you have about 300 watts this sub will play just fine. Ebay is an good site to find a good deal on sound. So it depends on what you want. Door speakers is what you want to pay more for. Only because you don't want to hear the voice Sound like crap. Bass is cheap and a Clear voice for mids and highs cost and lil more. But you can always find a good deal out there. Have fun.