@thecarpathian
"Do you hear any appreciable difference with your thermal magnetic switches in?"
The only physical changes were adding a thermal magnetic switch in the wall to the hot wire feeding each amp, and then removing the (pretty good - recent SR color) fuse installed by SMc Audio and replacing it with a1/4-inch, 99.9 percent copper rod that was burnished smooth.
To your question, no, I do not hear any appreciable differences that I would reliably attribute to changing out the fuse for a thermal magnetic switch. I am not surprised. However, I do get to turn my amps off without unplugging them or turning off the breaker at the main electrical panel so I am happy with the win.