Keith-
I think the additive is called MTBE (I can't remember what that stands for), somebody correct me if I'm wrong.
The effect of the additive is to oxygenate the gas. It is designed to reduce emissions. The only true effect is that I am aware of is that gas mileage is reduced apx. 15%, power is reduced and I know a lot of gas station attendants complain of headaches and nausea when they are forced to switch to winter gas.
I don't know there is much you can do about it, other than stock pile a couple hundred gallons of summer gas (But the way those 2 4's suck gas, that probably won't be enough for you to make it through the winter anyway
)
I didn't think that they put that stuff in the gas down by you- I thought it was only a Northeast or cold climate thing. If you look on gas pumps by you there should be a label which says that the gas is oxygenated or that it contains MTBE (or whatever the correct name is).