Ive never heard of it? I just make sure to never get below like 1/3 tank in the winter. Its been everywhere from 0 to -30 the last week and I havent had any troubles(where is the knock on wood emoticon?)
Are you talking about the stuff you pour in to get rid of moisture in your fuel? If so i never use the stuff. I live near Chicago and it has been -30 windchill the last couple of days and I only had 1/4 tank of gas. No problems at all. As long as you know that you are getting good gas at the station (no water) then you should be ok.
First of all, I've never used it in my entire life. Just buy from a high volume retailer and you'll be fine.
Secondly, gas in New Hampshire contains ethanol this winter. That's basically the same as drygas! The alcohol mixes with the water and lowers the freezing point and allows the mixture to be burned.