Ok, here's the question. I have a '00 Nissan Altima, with 6-1/2" Alpine Type-R componets in the front and coaxials in the back. They sound great now, but I'm sure they would sound better with an external amp. I'm not sure on what amp to get. I'm thinking a 4-channel amp that can put out between 50-70 watts RMS, but then again I'm not the expert. I'm looking to spend under $300, any suggestions?