I agree with Alpine as well, the way you break in your motor and keep it tuned has more of an impact on engine life than the fuel. Granted there are some better fuels than others, for instance I have never heard anything good about Blue Thunder, but I have heard good things about O'donnells, Byrons, and a few others. I prefer to use Byrons Race 20%, mainly because even when tuned right it still gives more smoke than the Traxxas Top Fuel I got when I bought my LST, I like to see plenty of smoke when its tuned right. Anyway I am a gallon and a half through my Axial with Byrons, and it is still makes me think I am gonna break the pull start when its cold.
-AxialLST