The challanger amps I think start at 115 watts then progress to 180 watts triode power.
The manleys,vtl, and quicksilver amps I have seen average in the 90 watt range and then progress;there are models with lower power but I personally would not consider anything less than 100 watts to really drive and control the panel of the SL3;maybe a person with this speaker experience will respond to your post as I can only relate the my m2's which are a full range panel which would be similair to the logan cls speaker.
The manleys,vtl, and quicksilver amps I have seen average in the 90 watt range and then progress;there are models with lower power but I personally would not consider anything less than 100 watts to really drive and control the panel of the SL3;maybe a person with this speaker experience will respond to your post as I can only relate the my m2's which are a full range panel which would be similair to the logan cls speaker.