Does bi-amping only benefit sound quality if your really driving your amp hard? I have a Mark Levinson 23.5 which is pushing my B&W 801 series 3. This amp is a beast and I never push it anywhere its max. I have an opportunity to purchase another 23.5 but don’t want to buy it just to buy it. If i’m not going to benefit in sonic performance, I wouldn’t want to do it. Any thoughts?
bi-amping benefits sound quality if you're listening only at one volume setting and only on compressed and limited recordings.

other cases single amp is much better.
Monoblocks should have a definite improvement on sound reproduction.
Especially if you can put them as close to the speaker as possible.
Short speaker wires will improve sound considerably.
To get the real benefit of bi-amping you need to add active crossovers and bypass the passive crossovers in your speakers.  Then you'll need some measurement tools to dial in the crossover frequency, slope, etc.  A lot of work but definitely worth the effort, on my Matrix 802/3s.
If you are looking for better performance consider getting the Bass Alignment Filter and Bi-wiring. Your speakers as is, due to the box size and the way they were tuned, will play down to 39 hz. They do not play the bottom octave. If you want to hear the bottom octave consider acquiring the Bass Alignment Filter, that they were designed to be used with. 

39hz - 20khz without the BAF
20hz - 20khz with the BAF.

The BAF would give them potential for full range down to 20 hz. But they still need to be spaced properly in the room to achieve this. I show a past pic of my 801 (room and spacing) in my virtual system.

Good luck

Depends on a lot of things, how difficult your speakers are, where they are difficult, and how solid the power supply of the amplifier driving it is.

There's one major benefit to using bi-amping however, and that is the ability to use a DSP eq on just the bass section. This allows you to get most of the benefits of a dedicated/room corrected subwoofer, without having extra hardware between your speaker and DAC for the mid-treble regions.