[Buffrock]

There is far too many variables still. are you running the factory spks with the 4 channel and the sub on the sub output? Regardless you probably don't want the rear spks playing as load as the front as the setup in dirtyd's link sugests. Set it up by ear as per 72 Cheyenne's post. I've set up plenty of large systems with factory reps and the only time we used a meter or scope was to balance amps in multi amp SPL vehicles.