Which model Bryston with Vandersteen?

I'd suggest you go with the Bryston 3BST or 3BSST for the 2's now and worry about amplifying the 5's when you get them.

if you get a three bryston and add two q subs by vandersteen you won't spend the money on five's buy music

The price difference for a used 3B-SST vs. a used 4B-SST is not large, and my long-term experience with Vandy speakers (any model) is that they perform better with more power rather than less. Therefore, I'd recommend the 4B-SST.

I am using a 4B-ST with my Vandy 3A Sig's, and intend to use it (or a 4B-SST) when I upgrade in the near future to the Vandy 5A's.