To do everything. Installation of everything. And a place that has warentees, and won't likely to go out of buisness anytime soon incase something breaks.

Edit: And how badly am I under powered? Also, what would be a good amp for the single type-r sub? Would this be good?

http://iweb.alpine-usa.com/pls/admn/...=140&p_main=10

But it's mono, so would that be bad?

Another edit: If I got these speakers:

http://iweb.alpine-usa.com/pls/admn/...=104&p_main=10

Without and amp, how badly under powered? And with the amp, dangeriously over powered?