For Carver, I believe the later TFM models are higher current and would work better with speaker designs that are more current hungry and have more difficult loads.
I had an m4.0t Silver Seven prior to my current Musical Fidelity A3CR. That model delivered a lot of watts per dollar but was not high current. It sounded very good with Magnepans for example when I had them but low end was impacted at lower to moderate SPLs driving more current-hungry designs, like the OHM Walsh 5's in my system. When cranked to higher SPLs , it still sounded very good for the money with the OHMs.
I had an m4.0t Silver Seven prior to my current Musical Fidelity A3CR. That model delivered a lot of watts per dollar but was not high current. It sounded very good with Magnepans for example when I had them but low end was impacted at lower to moderate SPLs driving more current-hungry designs, like the OHM Walsh 5's in my system. When cranked to higher SPLs , it still sounded very good for the money with the OHMs.