Check to see what retubing the amps will run as well. Upscale Audio can help you on tube cost and them being a Cary dealer can give you an idea of what a fair price is. If it has a fresh or fairly new set of tubes I’d guess $1800 and if you need to buy new tubes subtract that cost or most of it. If he has the original packaging that will add value. Just remember they’ll run warmer so if you live where it’s hot or have a small room that may be an issue and you’ll have tube replacement cost over the years.
I’ve always preferred tubes on the earlier ML speakers so who knows. Shipping cost might bite you so weigh that in as well. They Carys will likely hold their value much better than Vincent hands down. If you do make the move, get longer power cords and keep the amps closer to your speakers if you can. Be warned you may find out your NAD will not be in the same league sonic wise.
Good luck