I think it’s going to take Fred awhile to decode what the MFs are bringing to the table (or taking off the table) besides the added power. Right now he is giddy with what they are bringing to the table, but it remains to be seen if long-term happiness will result (and I’m not saying it won’t).
I don’t think there is any free lunch, and I don’t know that it is possible to lash up a tube amp to a SS monster amp and expect only an increase in available power output and no added sonic signature from the SS amp. It seems to me that adding the Super Chargers is mixing and matching colorations from two different technologies. I believe that you can run the Super Chargers as straight up power amps can’t you? If so, it would be interesting to hear them without the tube amp in the signal chain and see if the sound gets better, worse, or just different. I can’t get past the feeling that if the Super Chargers are totally tonally neutral, than that means you are using the preceding amp as a tone control.
A tube tone enhancer? Even if the big iron is neutral, and it's probably close enough, it will still add a hell of a sonic signature. Sufficient headroom and driver control is a sonic signature, and a very good one, indeed.
Tim