BAT REX amps

I would appreciate input from people who have upgraded to the BAT REX amp (either Mk. I or Mk. II) from the VK-75SE. I would also appreciate any comments Victor ("Chipmunk") would like to make about important technical differences between the two amps, for example, do they use the same output transformers and have the same energy storage? Is the basic difference just better quality parts or are there also differences to the circuit?

Thanks in advance.

I would interested in hearing from owners of the REX pre-amp as well. If you guys have a local dealer/retailer that has these models for audition, please give a shout-out.
Keep me posted & Happy Listening!
Jafant, we are a BAT dealer located in SoCal and have the REX 2 preamp available for audition, not sure where you are located. We also have a demo pair of REX mono blocks for sale on Agon - 50% off.