I know this questions has probably been answered on here some where, but is it possible to keep the factory head unit and install new subs and amps? I'm pretty savy in hooking up sound systems, but they have always been on after-market head units. I have a 04 LE with the Rockford Fosgate sound system. If I can just figure out how to run RCA cables from the amp to the stock stereo, I should be in good shape. I guess I will also need to run the remote wire. Anybody know of a product that can do this???