Since you mentioned running in mono, I think what you’re talking about is running the 2 Evo 400s as mono blocks with one amp driving each speaker throughout the full frequency range…That’s definitely possible and should make some improvements, the value of which would be relative.
Bi-amping a speaker means using a different amp for the tweeter than for the woofer on the same speaker. That setup would require one evo 400 driving the lows and the other driving the high frequencies each still set in stereo and connected to separate binding posts on the speakers… you can’t do that without separate binding posts unless you’re going to do some surgery on those beautiful speakers. I would not suggest this plan.