Can you overpower a speaker

You do not need to over excursion loudspeakers to cause damage to much power can cause voice coils to melt they are dam close to melting in most conventional loudspeaker designs to begin with. So doesn't take much extra to cause damage. 100 watts into most any transducer is or near causing a melt down in voice coils. Most VC use glue this can melt before metal, hot cool cycles will eventually cause a open circuit since coil is broke no connection. I have seen this damage in modern loudspeakers far more than any other type of damage except physical ie drop smash cones pushed in.

Let me ad this.I should have also said to much power can fry your speakers to.Not just to little power.Again,keeping the volume set where you don't get any distortion,or other sounds coming out of your speakers,that sound wrong when you start playing them to loud.When something starts sounding bad,back the volume down,until it sounds right.

How about this option: Get a pair of killer subs. If you use them with a high quality crossover it will alleviate a ton a strain on your amp (since bass is power hungry) and help to protect the speakers from being pushed too hard. A huge pair of REL's will give you all the bass you could ever want, protect your speakers and add hundreds of watts per channel...

There are ratings for reasons;answering you question on wanting massive power in my opinion is fine if applied properly and understanding the consequences if used improperly.

To Elevick's suggestion, it's great if you are using speakers with high-order crossovers and it will certainly give you the impression of more horsepower and protect your primary speakers, but if you are running speakers with simple first-order crossovers, then using an outboard crossover is going to kill all of the benefits that first-order crossovers bring.

Also, getting back to power generally, you ideally want an amp with a lower continuous power rating (darTZeel, Ayre, the new Rowland 625) as I explained above, but also an amp with a very stiff power supply that can deliver huge amounts of instantaneous power. Such amps, such as the big Naim amp and the CAT JL1 monos, seemingly have the power of a 500 watt Krell, but without the drawbacks.