I'm running an Alpine Flex4.... cheap amp (money-wise) but I personally think it's great quality. I'm just using a Kenwood monoblock amp to power my fosgate xlc subs in the back.

By the way, anyone else hate it when someone has crazy ass bass coming from a couple huge 15" woofers in the back and no amps/replaced speakers for their mids/highs? Personally, I think it ranks up there with the... well, basically it's just plain stupid. MHO.