Congratulations Rudy, I can't think of anyone better for such a job and can see why they contacted you.

Everyone has covered most things you need to consider but one thing that springs to mind is that this opertunity may never come again and if you don't go will you be forever asking "what if"?

You have the talent Rudy, you are wanted in the right place, to do work that you are exceptional at.
This sort of opertunity doesn't come around every day and if the prospects are good it may be the best move to make.

All the best in whatever you decide. 8)

Catlin