REF1000 was stock Icepower in a box. Ref1000m added power supply board and input circuit board for higher input impedance to match better to tube preamps. Wyred added similar input circuit board as well only last I checked.
So the differences vary between various BC models and Wyred with original BC amps being most basic Icepower, Wyred the next most refined and m series BC amps the most refined over base level Icepower.
Relative prices reflect this hierarchy in regards to technical level of refinement over base level Icepower.
One would expect a general corresponding difference in levels of performance possible however that could vary case by case depending on exact system used in.
So the differences vary between various BC models and Wyred with original BC amps being most basic Icepower, Wyred the next most refined and m series BC amps the most refined over base level Icepower.
Relative prices reflect this hierarchy in regards to technical level of refinement over base level Icepower.
One would expect a general corresponding difference in levels of performance possible however that could vary case by case depending on exact system used in.