Amp comparison

IMO, the ARC 150SE is significantly better than the Ref 150.  I own the 150SE and previously the 150 unmodded.  

@bigkidz 

Rolling the KT-150s in the Ref 150 made a noticeable difference.  Deeper and tighter base, smoother range.  But the SE mod took the amp to a different level.  Bass was tighter still, more open and transparent, better control over the speakers.  
But to be candid, I made the switch over to the SE version many years ago so it is hard to be very specific on details.  That said, if you have a chance to A/B the regular 150 with the SE version, the differences will be day and night noticeable.

FYI, based on a conversation with Kal at ARC, I understand that the GS 150 is the same as the Ref 150SE, just a different skin.  The specs are identical.  In any case, you can refresh what I understand by calling ARC.  There is a new guy who took over for Kal, … forget his name.