I'm in the market for a new 4 channel amp to push my audiobahn front 4" speakers rated at 80 watts rms and my rear infinity kappa 6 x 9 rated at 120 watts rms. My budget is around $300 and I just want the best 4 channel amp in that price in my budget.
For that, I would look at the options you have. You could get some more intense front speakers, where you will be sitting and that's more important anyway, or get some weaker rear speakers and keep the front one's, one's that moreso around 80 wrms. I wouldn't get anything more than 80 wrms if you want to keep the front ones, Audiobahn's can't handle a lot of excess power. You could save some money by getting a Directed Audio or a Profile Amp, or get something like a Fosgate or Phoenix Gold. Remember you're going to have to get about a 8 or 10 gauge amp wiring kit, at least 10, and like 50 feet of 14 gauge speaker wiring, or even 12.