[Rolex]

If the performance tune requires premium fuel I would say yes. Premium fuel in my area is 93 octane. E85 (depending on the blend - 70-85% ethanol) is closer to 105-107 octane. You'll probably notice it runs a few degrees cooler and has a better throttle response. If your programmer advances the timing a good bit you may also notice it takes longer to crank the engine on that high octane fuel.

When in doubt, call the manufacturer customer service before leaping.