Hmm. I don't know much about subs. But I would try and find a good cheap 5 channel amp. My friend got a used Kenwood 5 channel for like $75. Works like a charm. That's what I wish I could have done, cause now I'm trying to get a sub into my setup for cheap. Browse around on Crutchfield and Sonicelectronix. Check out Diymobileaudio.com. Great car audio forums.