i have a 96 a6 and I was wondering how hard it was just to swap the bose amp in the back with something like an alpine 4 chan. amp. Or do you have to rewire the whole car? (i already wired the deck). And When/if i replace the speakers can i just swap the old speakers with the new speakers?... I was always under the impression that the wires all had to be replaced. Any help would be greatly appreciated.