You wont need to worry about wattage from a head unit. They all lie about their output. They'll say "50w x4" when you'll only see about 15w. But if all you're wanting to do is add an aux you can go this route....Amazon.com: GM12-AUXV2 PIE Adjustable Auxiliary Input For 2002-2005 GM / Chevrolet / Cadillac / GMC / Pontiac Class II Radios (GM12-AUXV2): Electronics