Too powerful of an amp!?

All great advice.  An important aspect of matching amps and speakers is synergy.  The watts alone won’t tell the full story on how they’ll pair together.  Another poster brought up Horse Power under the hood which is a good comparison, it’s not just HP though, it’s Torque, it’s how a car is geared and various other factors, it’s when the engine in a car has synergy with the rest of the car that true magic happens.  Same with speakers and amps.  Research what mates well with your speakers, Tube or SS, do they need headroom to really shine?  Are the speakers on the brighter side?  Pairing Tubes or Class or SS amps known for warmth like Macs, Pass, Krell, Parasound, Cod to name a few.  Your speakers will likely do very well with amps that have some headroom, provide stability.  If you like Mac’s, a great place to start with their power / autoformer technology.  Good Luck, enjoy the journey! 

@carlsbad2  +1 - Carls is right - we typically use very little power for most listening.  A clean amplified signal is better, even if it is 'only' 100 watts.  In my system I bet I only use the first 20 watts before it is too loud.  

I always had over powered amps with lots of headroom. It’s always been beneficial I find. I am now at an extreme point where I already had a Mcintosh 300 watt per channel and I bought Avantgarde speakers at 107 db efficiency.
That means that I hardly use two watts. I am not bothered by the amp not working hard, but rather the question always goes through my mind that the preamp volume is always in the lower area. I keep hearing that a preamp works best between 75% and 100% (unity gain).

So to your question, I would say, an over powered amp yes, but are we getting the best out of our preamps that are always in very low volume setting?

I do understand that there are many ways of attenuating signal but speaking in general here, I believe most preamps work best between 75% and unity gain

Great point on running your pre-amp in its comfort zone was made by @kld10  and it gets to what I read elsewhere recently.

I recently read somewhere on this site about running an amplifier within its ideal power range.   Not running 12watts into Maggie's at low volume, you're still pushing it some and out of its comfort zone. Not running 600 watts into horn speakers, using the opposite end of the power band with its own issues.

It would seem advantageous to me. Individual components might vary in their zones, but it's the general idea we're bringing up.  (If I have to go up or down, I'll always have more power, never less though.)

Yes you can as long as your are use the volume control diligently. Also many often overlook the input sensitivity of an amplifier and when using preamp, this is where synergy come into play. Keep in mind that this applies to separates and not much into integrated amplifiers.