Update on this. Thanks Tony. I trouble-shooted the "only playing out of 2 speakers" problem by using a portable CD player. I found the player played out of all 4 fine straight into the amp, but only out of two up by the dash. So, it was the RCA's from the amp to the dash. Circuit City says they were pinched by the back seats. They gave me new RCA's and I get sound out of all 4 speakers now!!! It sounds great, except I still have the power thump and I now have the dreaded alternator whine. I thought it was the sled, but they have grounded that really well. Just wondering if I should get one of those Alternator Noise Suppressors or Amplifier Muting Circuits from Crutchfield. Anyone have luck with these??