I have Alpine SPS-171A 6.5 components in the front, and Alpine SPS-690A 3way 6X9 speakers in the back. I was about to buy an Orion Xtr500 amp (2 channel 500 RMS) but i was told by a friend that you should get an amp with 4 channels because it would make the sound quality better. Im not going for the cheapest amp, but i would not like to spend too much. any suggestions/comments on how many channels/RMS power to run to my speakers would be great - thanks