I would try to negotiate a good price šjust in case as a buffer. But in general beside Rolex, AP and Patek, Journe and some independents everything else tend to lose value. I am talking also about less valuable pieces it is quiet possible that these very amazing and complex tourbillon are much more sough after and won't lose value. At the end of the game you should buy what you like to enjoy! I don't think watches are a good asset class.