The factory amp is a 7 or 8 channel, left and right dash (dash center speaker is piggybacked mono off the left/right dash outputs), left and right front doors, left and right rear doors, and a dual voice coil sub. I've read here (or at CT, I can't remember) that it's all crossed over in the amp. The dash is high passed, the front doors are band passed, the rear doors are full range, and the sub is low passed. This makes sense to me, but I'm not sure if its true because Tech and P-Diz advocate installing the REQ post amp in the RF system but I don't think they've said which outputs to tap. If it is crossed over in the amp, it seems that the only outputs to tap would be the rear doors as they would be the only full range outputs.Soonerdude said: