get a speaker specific amplifier and you can plug it in, but the volume will be very touchy.
I have a 1982 Chevy Monte Carlo and my head unit was stolen. I didn't particularly like this HU because it did not have an mp3 (line in) input. What I want to know is...can I connect my portable mp3 player(creative zen 30gb video) in anyway without using a head unit? I have 2 front speakers. 2 rear (4x10, the Monte Carlo doesn't support 6x9). I have a jensen (I know it sucks, but its 750 watts) and 2 12" woofers. What suggestions do you guys have?