I have SP100's which are pretty much the same as your S100's, and I have found the Spendors to be very easy to drive. I have used them with amps ranging from SET tube amps with 8 watts or less to, at the other extreme, a Classe CA300 with 300 watts per channel. In my experience, with the various amps I have tried on the Spendors, they seem to do best with push-pull tube amps in the 30 watt range. But the issue is always the sonic quality of the amp, not the power.
My dealer strongly recommended not using the tri-wiring. He said it was more important to use a single very high quality wire and then quality jumpers to the other terminals. That's what I have done during the 12 years I have had my Spendors.
I would be very hesitant to try bi-amping or tri-amping. Just because there are binding posts for each speaker doesn't mean it is a good idea to drive them separately. One of the really nice things about the SP100 is its coherency, and you risk losing that when using different wires or different amps for each driver.
My dealer strongly recommended not using the tri-wiring. He said it was more important to use a single very high quality wire and then quality jumpers to the other terminals. That's what I have done during the 12 years I have had my Spendors.
I would be very hesitant to try bi-amping or tri-amping. Just because there are binding posts for each speaker doesn't mean it is a good idea to drive them separately. One of the really nice things about the SP100 is its coherency, and you risk losing that when using different wires or different amps for each driver.