Got a 600watts amp with 2 subwofer from my old Montero and wanna put this on a X52002, my good friend havent installed on a BMW yet and this store Audio Express inReno, Nevada wants $250 just to install the speakers. Wow thats way too mkuch. its just the Wires and putting it on. How much you think will cost me, do i need a plug on my stock system came with the bmw in order to have a extra output for the amp? Anyone know in Reno Nevada good Radio installer? thanks in advance