My receiver is a Yamaha 1400. It is rated @ 110wpc.
My amp is an Adcom 7605. It is rated @ 125wpc.
My speakers are 4ohm with a sensitivity of 87dB. They are hard to drive. So, even though I didn't double my power, I achieved a major improvement at high volume levels. And, I took the strain off of my receiver. The music remains clean and detailed as the volume increases, instead of loosing detail and becoming distorted.