Use what sounds best to you. As for me, I think the Vandy's benefit from some extra power, but I'm not listening to your rig.
What about power for Vandersteen 2 speakers?
I have three amps I can use, 50w YBA, 100w Krell and 200 wpc Rotel. I listen to jazz in a small room and as long as I don't get silly with the volume the smallest amp sounds the best. I know Vandersteen rates the speaker between 40-160w but it works fine with the 50w YBA amp. Is it better to use more power or should I stick with the better sounding YBA?