I can see using 91 with the Dynatek cdi but I think even that is a waste of time with the stock piston... it's only 9:1 compression...
If you gonna do it anyway get the unleaded...
If you want to gain something get a piston at between 10.5 and 11.0:1 and run 91 unleaded pump gas...
Even then it won't be much of a power gain but the aftermarket piston will increase reliability...
And if you are going to the trouble of taking the top end off you might as well bore it and get a cam...and if you are going to do that you might as well get the head ported with +1 valves...
You already have the suspension, cage, intake, exhaust, cvt...
You are all set for a benchmark 693 top end...
You will be able to roost on Dan at will...that would be worth the money wouldn't it... :biggrin: