Yes, all rubber/neoprene/incompatible tubing and hoses in contact with E85 need to be replaced. Gravity feed, so no fuel pump issues, thank goodness.
I think there's an o-ring in the big Keihin carb next to the needle valve that I'll have to swap out for something in Viton, too.
I was tired of screwing around with retarding the spark, thicker head gaskets and octane boost additives, anyway.
Those big domed pistons and hemi combustion chambers really put the squeeze on the fuel/air mix, so 105 is actually a good fit in my particular case.