you should be asking yourself how well can I tune a motor...At 8% oil there is little room for error. The higher oil content fuels are better for people that are not tunning experts.

I use Odonnels 30%(which also dyes the motor yellow/gold) with great success. Once tuned, I rarely turn a needle and use the same plugs for what seems like forever on my motors. I would also try Byrons, have herd good things, but I like to tune my motor by sound/performance and I cant hear it well enough at the track, Soooo I stick with whats worked for me.