got my sub and amp now, just about all wired in (as in, fed from HU to boot) but its rainin so gonna leave power etc till 2moz. anyway, quick question. the earth cable that came with the kit aint as long as i'd have liked. i know someone said earth to wheel nut thingy, but due to size of the sub and the fact the amp will be screwed to the sub box, the only place i can think of earthing to is one of the screws that hold the rear light unit in. would that be ok/advisable?