i am interested in Bad Cat Black Cat or Matchless HC. 1. are there any tone difference between the older Bad Cat and the new one with K master? some says the older one has better tone... so wonder it is true or not. 2. does Bad Cat retrofit the order model to install K master circuit? or does they retrofit Matchless for K master? 3. are there similar retrofit options to K master? for ex, how about the 3rd power HybridMASTER?