My amps, crossover, XM tuner, and power inverter are mounted to the side panel behind and over the driver's wheelwell. I've made new side panels out of plywood and carpet though. I doubt the cardboard sides would support any weight. I have a 2 ga feed line and the remote line going up the driver's side to a 4-way fuse block, and the RCA and IP-Bus lines up the passenger side A pillar, straight back and across, then down the driver's C pillar (this keeps alternator noise from crossfeeding into the audio and data lines)
Matt {peace}