Magnepan difference of 20 and 20.1 ?

I would appreciate a response.
The 20's midrange panel operates in single ended and the 20.1 midrange panel operates in push pull like the other panels.
20's like to be biamped with an active crossover, and the 20.1 sound better single amp and passive crossover. Or you could say the 20's didn't sound as good with the passive crossover.
I have the 20's and think that I have solved the problem for me. I tried a Bryston 10B active crossover, crossing over at the points and slopes recommended to me by Magnepan but never heard the order of magnitude difference I was led to expect. I switched to a CJ Premier 8a with Teflon V-Cap and other upgrades. We additionally upgraded the passive crossover boxes with much higher quality caps for the High Pass section and Gold over silver internal wiring as well as the "shorting" wires for single amp operation and high quality Kimber Kable 8TC for the speaker connectors from passive crossover to the speaker panels. I now feel that the single amp observations by Cytocycle above apply to the 20's as well.