Is there a such too much power for speakers?

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. 

As for your question of soundstage, the preamp, amp and speakers all contribute to the soundstage. Clean power and plenty of energy storage are crucial. 

Wow thats a tough one.

@nasaman ,
One of the underlying benefits of having an 'excess' of power is that the amp will not be coming anywhere close to its maximum power output.
When operating in its comfort zone, an amp will have lower distortion, and sound 'better'.
A very simplistic description. Hey, I'm not Almarg.
Bob

fundsgone62 - Sonus Faber Cremonas are hard speakers to drive. I agree they require a lot of power (actually a lot of current) to drive them due to their phase angle at low frequencies. I tried multiple amps on them and ended up with Mark Levinson 432 with 400 watts per channel. However, other speakers can be much easier to drive. It depends so much on the design of the speakers.