A:Answer Never mind. I called Onkyo and got my answers myself. Per Onkyo there's no pre-amp in/out so no way the 901s will work. Per Onkyo, this receiver is 4 ohm safe and more than capable of driving the speakers I am interested in pairing it with (Magnepan MMGs). Thanks to Onkyo customer service for taking the time to answer me via telephone.
I will not be buying a TX-8160 at BB unless they step up to the plate on a recent laptop purchase that has gone to a minor level of Hades. Regardless, this is a great receiver and BB in general have been excellent. Hoping they still are. Thanks.