I want this to be a learning thread, if you have questions, ask, knowledge, share.
Based on my experience with E85 and E47 (half and half with 93 pump gas which is 99 octane)
On a stock fuel system I wouldn't recommend it, you are correct, the rubber lines and incompatible materials will degrade and eventually fail. Without a tune, you will likely not gain any power NA, you can throw a lot of timing at it and maybe gain some power if NA, but you're going to need a good dyno tune with a PC3, or use a PC5 with autotune and a POD-300 for logging like i do. No need for dyno tune if you know what you're doing (I do).
Often everyone just takes the general things they've heard on the web that its bad, and bad for your bike. Well in a sense, if you're using rubber lines and no tune, it'll degrade the lines over time, and it can run very very lean, and lower mileage by about 30%. However, the benefits of it being cheap, high octane, knock suppression, chemically cooling the air going past the injectors, and awesome with high compression and timing are pretty awesome if someone was willing to try it out.
The downside? Initial cost of switching shit over to compatible material, tune, and limited availability. It sucks because I'm limited on how far i can go away from my fill up stations now.
What is needed to switch:
Compatible fuel pump, fuel lines made of of compatible material listed below, compatible fuel pressure regulator with return, larger injectors are favorable but I know a trick and am using my 2003 stock injectors (no its not upping the fuel pressure i run a base of 55psi), and most importantly a good tune.
Some info:
E85 (105 octane) is very very forgiving on its AFR if you are off a bit, most likely it still will not knock, its 105 octane, 85% corn alcohol. You are more likely to fuel knock if you go too rich. It has a natural chemical cooling effect on the air coming into the ITBs.
E47 (99 octane) is great because you don't need to add about 30% more fuel like on full E85, more like 15% which is doable in most cases without going larger injectors or modifying stock ones, but you'll have to mix equal halves of 93 and E85 at the pump, not that difficult just two card swipes. I did this for years on my daily car (yes it needed it).
Overall, what am i running. I am running full -6AN 316 stainless lines, fittings, walbro inline fuel pump, rising rate 1:1 FPR (55psi base), stock injectors modified by myself, PC5, autotune, POD-300, and have street tuned the bike running 11.7:1 on the gas scale or .80 lambda on full boost, otherwise 13:1 cruising. Its a turbocharged 03, non intercooled (chemical intercooling thanks to E85) on 7psi low boost or 11 psi high boost. Stock compression, not pulling any timing and it runs absolutely wonderful. E85 loves high compression and boost and timing. You have to try damn hard to get it to knock honestly. I've run 25* (93 octane would only hold about 17* safely) of advance on my 67mm turbo car from mid range up to redline and it never ever knocked and it made a TON of torque.
Runs just fine:
https://youtu.be/Jz6jPKc6tdE