i have an amp (sony xm 2002gtr) that says it requires 4 gauge wire..but they cost $100+ and i have plenty of 8 gauge wires. can i use two 8 gauge wires as a substitute for one 4 gauge wire?and also, i have my capacitor grounded to unpainted metal of my car AND the ground port of my amp..is that incorrect?
Two 8-gauge wires combined are equal to a 5-gauge wire, but that should be close enough for that amp. Make sure each wire has its own fuse near the battery; 40-amp fuses would be a good choice. If you capacitor is connected to ground, and your amp is grounded, then you don't really need a wire between the capacitor's ground terminal and the amp's ground terminal. It doesn't hurt anything, though. If the only ground wire at the amp is the one that runs to the capacitor, then you're better off connecting the amp ground directly to chassis metal.
