My Musical Fidelity A3CR is about 120w/ch into 8 ohm and almost double into 4 and does fine with the 100 S3s in my rooms that fall within the max room size recommendation for 100s.
I can also say that all the 100 s3 and larger drivers love lots of power and current, the more the merrier.
I had them on a Carver 360w/ch amp prior and neither 100s or larger 5 drivers ever winced being driven to very high SPLs.
I've also ran the 100s to great effect and without issue using an 80W/ch Tandberg 2080. This was not enough for the larger 5's though IMO in that the dynamics suffered, though they were still perhaps undergoing break-in at the time.
Switching to the Audio Research sp16 tube pre-amp recently also resulted in a major improvement in overall dynamics, both large scale and micro. The improvement in microdynamics and transients in particular was much greater than any I noticed with various amps.
Others report and I tend to believe that in general the more power and current you throw at the Ohms, the better the dynamics overall become.