Originally Posted by toyota_aristo

Are you upgrading your battery as well with a higher Amp battery?
The reason the current wire is 8awg, is the car manufacturer's engineer's calculated it according to the distance of the wire and the current draw. If your going to relocate the battery to the trunk, that calculation for an 8awg wire may not work safely. Bigger is better as far as wire gauge is concerned. There are calculations to figure these things out, but you need to know the amp draw and wire distance you're going to use, at least. You don't want to install a small wire and have it burn up on you because it's drawing more amps than what it's rated for. Good luck.