Picked up the Starke Sound AD4.320 and got it added to my setup running my fronts in bridged mode. Pretty happy with it, definitely cleaned things up when pursuing higher volumes. Downside is I've now got a ground loop hum where I've ordered a bunch of stuff to resolve.
AVR is "double insulated" so has no actual ground, amplifier has a ground. Even with all inputs removed from the AVR I still get the hum. I've got a jensen isolation transformer on order that I plan to utilize between the AVR and the amplifier which should resolve things but I guess I'll find out.