I purchased a used pair of Vandy 5As last year in pretty good overall condition to replace my 5s which were in poor overall condition (I bought them cheap that way). I have driven them with a 100wpc Counterpoint stock power amp, a Lafayette KT-550 tube amp 35wpc, a Luxkit Class A amp 40-50wpc and the amp that we build hybrid 6SN7 power amp. Since you are really only powering the top half of the Vandersteens (powered subs). Each amp drove them with ease. I have also used a 200wpc hybrid amp that we built and that sounded excellent but it was not night and day with the more watts just a little more relaxed sounding. The smaller hybrid we just built may be the best sounding amp I have heard on the 5As. I heard the Wilson S1s at a dealer many years ago and liked the way they sounded. Before the price dropped on a used pair the model 2s came out so I never went any further. The 5s are pretty well balanced top to bottom and the bass is so adjustable that you can pretty much get them to sound good in most rooms. You can find them used in the $6K price range and I think there was a pair on US Audio Mart recently.
Happy Listening.
Happy Listening.