Vitus RI-100 And REL G2 Sub Wiring Experience?

Any comments or advice from current Vitus RI-100 Integrated Amp owners who are using it with REL G2 subs or any REL subs for that matter - even past models like the Stentor and Studio? This would be a two channel only two subwoofer configuration using the high level neutrik connection from the sub to the amp speaker terminals and/or the chassis. Its not clear if the RI-100 is differential or standard or some kind of hybrid - thats why some real experience with successful results would be very helpful.