if i understand 'all pre-outs to a stereo amp',then that will "matrix" all info into front left and right which will probably be less than satisfactory.keep your center and surround on the receiver and use a stereo amp for mains.

no doubt you'll have to recalibrate for movies,but when you wanna tear up some good 2-ch music you'll have the power.

and yes,you will have control of all channels from the pioneer