Do high dollar mono blocks truly improve the Sound Quality over the mid tier amps

I think you might see a bigger improvement by changing your preamp. You have good amps.

t 

only if the upgrade exceeds 57K

 I've been considering upgrading these amps to the next price/quality level.  My biggest concern is whether I'll get the level of improvement in SQ that will move the needle.

@skinzy 'The next level' has little to do with price just so you know. High end audio isn't driven by price (although many think it is), its driven by intention.

On top of that there's something called the 'Veblen Effect' which causes people to think that if they spend more money they will get more value. Sometimes that's true and sometimes it isn't!

Put another way it sounds like what you really want is something that sounds better. That may or may not be the amps. FWIW, sound quality always starts with the source- get that wrong and nothing you do downstream will sort things out. If the source is right, the preamp is the next step.

Since you are running a balanced power amp, consider this: there is a standard for balanced lines which I've found many high end audio manufacturers seem to ignore. If the standard (AES48) is supported, then you'll find the interconnect cables to not contribute to the sound of the system- they will be far more neutral (which is part of the goal of using balanced lines, other than elimination of ground loops).