its been a while since ive installed a system, but im gonna put one in for my friend probably next weekend. he has a 2002 grand prix gtp, and i forgot what wire do i hook the remote wire up to. his head unit is stock, so i know he needs to buy a little adapter for the rcas. and he also wants me to try and amp his door speakers...but he only has a one channel amp, so can i even amp his door speakers along with his subs?