Amp for Vandy 3A?

I think its a bit marginal. I used a pair of McCormack DNA 0.5s (100 wpc to 8 ohm) vertical bi-amp. For a single amp, I used a DNA 1.0 @ 185 wpc into 8 ohms. If you are fixed on the amp, I would go 2CE sigs which are selling now for very good prices used (ca. $800) and then add a 2WQ sub which come up regularly.

I second the McCormack for SS, hard to beat at the price and with the Vandersteens. Your best advice regarding your speakers will be from Richard Vandersteen. He will get on the phone and he is a straight shooter.

I run my 3A Sigs with Cary 211 AE monoblocks (70 w/ch in class A 8 ohms, 110 in class A2). My room is small but I never get even close to running out of power. I listen to large scale orchestral music (but not rock). The 211's have a lot of iron and a good power supply so those 70 watts are real. In general, I find that you need about double solid state watts to achieve the same subjective listening power from a good tube amp. In my case, that would equate to ~140 watts solid state (a loose rule of thumb to me).