im off to buy a ported 10 inch sub

ported? Eeewwww!

(Juussst kidding...) You will be very happy with the improvement in your sound from adding a subwoofer, whether sealed or ported. And you picked 10" -- my favorite.

Now, once it's installed, I want you to try an experiment: run the sub with the normal crossover (probably around 90-100Hz) and get used to how it sounds. Then, try it full range -- no crossover -- and see what you think. Chances are, it'll sound terrible -- but depending on the acoustics of your car and what other equipment you have installed, it might sound really good. It isn't supposed to, but every once in a while (like in my car, which the local stereo shop describes as "a freak of acoustics") it sounds great. If it works, you'll add a lot of richness and warmth to your sound. Just don't try "booming" it without the crossover -- those high frequencies will make it pretty unhappy (can you say "smoke"?) if you start pushing it towards its maximum power handling capabilities.

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"