Ok, I've got this ihead unit in my K5 I have Polk 5.25" 2-ways in the dash (2-50w RMS), I will have 6.5's or 6x9's in the back (20-80watts RMS)seat quarter panel area, and 1 10" or 12" sub. The question is, the head unit has a decent built-in amp (the mosfet45, 22x4 RMS). It has pre-amp outs for sub, or for regular speakers. I'm not really into big booming bass sound, just want decent sound at volume when going down the road with the top off. Should I get 2 amps,one to run the front/rear speakers, or 1 amp to run a sub and run the 4 speakers off the head unit, or 1 amp and run the 4 speakers off it and run the sub off the head unit?