i was wanting to remove my mach 460 system and upgrade to better speakers...the front speakers shouldnt be that hard to swap, but today i was looking at the rear 6x8's and the amp rack and i wasnt quite sure how to uninstall it. if anybody could help me out w/ how to remove the amp rack, im sure the speakers themselves wont be hard at all to remove. and also, how much do used mach 460 system sell for?