Over on Sebago Lake in Maine, there are at least 2 marinas that carry the ValvTect fuel. It alreadys has all of the additives and protectants in the fuel to combat phase separation for up to a year.
It's good advice to take matters into your own hands as far as when the boat is put into storage for the winter. Stabilize it yourself.
http://www.valvtect.com/marineFuelGasoline.asp
BT