Is there a such too much power for speakers?

How do I know the amp I’m looking to buy is beautifully enough power for my speakers?
what will happen when the power amp is (way) over or too much power for the speakers?
My Local dealer quoted, “there aren’t limits on power amp, (but my budget that is). The more, the better, they added”
Their suggested highest amplifications are in $75k range (my speakers are in $20k range)
Please help.
One issue is the gain of the amp. The gain needs to match with the gain of the pre-amp and the efficiency of the speakers. If you have a high gain pre-amp and a high gain amp and high efficiency speakers, you may end up with the volume control being in the very beginning of its range, which can be a problem. If you are only using the lowest 10% of the volume control, you do not have much control.

Many traditional high power amps are class AB, which means they are class A in the low end of the range and class B at higher outputs. Many people find class A to have a better sound that class B. So, where the amps changes from class A to class B can be important. A high output amp may have more class A range, but that depends on the design of the amp.

One of the reasons for high power, is to coup with low efficiency speakers with difficult phase angles. With easy to drive speakers, the high power may be wasted. But also look at the current the amp provides. High power with no reserve does not help with difficult to drive speakers. An amp in that range should double down into 4 ohms and again to 2 ohms.

One disadvantage of high power is that it makes it much more possible to accidentally blow out your speakers.

So, yes their can be disadvantages to high power amps.

$75K for amps and $20K for speakers seems like a mismatch. I would suggest listening to some lower priced options also.
Will over power amplification be crushing imagine, sound-staging and PRAT? Since inner details and dynamics are at peak. 
Go with as much clean power as you can afford. Your speakers are $20,000, so a good preamp and amp are in order. I had a pair of Sonus faber Cremonas, rated at 270 watts and 4 ohms, mated to a pair of Classe monoblocks rated at 600 watts into 4 ohms. I was never ever concerned with blowing the speakers - my eardrums are another story.

i recently listened to a pair of Sonus faber Nova iii’s connected to various amps, most with output over the Nova’s rated input. All sounded glorious. At ear shredding levels, I think the Mac was putting out 50-60 watts. 

Ive also listened to speakers connected to amps that are near the bottom of the recommended speaker power input, and the sound at higher volumes was not satisfying.

All of the amps that I auditioned wher in the $15000 range.

bring your favourite music, a decibel meter, and have a listen at concert levels.