Here is a common issue we often face. How to match the powers between receiver and speakers.
If the amplifier or receiver is designed to handle 8 ohm 2 x 100 W for the fronts, what's the idea power for 8 ohm speakers? if I match the receiver with 8 ohm 2 x 500 W speakers, is that a kind of waste on the speakers? if I use 8 ohm 2 x 50 W speakers, will the receiver blow the speakers? The numbers are arbitrarily used to demonstrate the issue.
I wouldnt get overly wrapped up in those numbers. If you have a 2channel 100 watt receiver, and are currently shopping for new speakers, just get the best sounding speakers you can within your budget. Remember, speakers are about sound....not listed power ratings.
It's the distortion that blows speakers. If you push your receiver to the point where it's distorting out of control, any speaker can be damaged regardless of their listed power handling.
If you currently own, and plan to run a pair of small 50W speakers off your receiver, they're obviously going to be a little undersized, and ideally, you'd want something bigger. Just dont go crazy with them and you'll be alright.