No E85 available near me. So not a consideration. Just don't want to do the work. And being a retired ase master auto tech. I know what kind of hacks are out there nobody touches my vehicles.
My vehicle was damaged before delivery. I was never satisfied with the repairs. So I raised hell with the dealer trying to get out of the sell for a damaged vehicle. Ended up recieving the Ford tune to accept the car and keep it. Was a shitty situation during covid purchase.
I have the ford performance tune and set it with the pro cal.
Also the 19gt's have the D4 trans. Putting in 4.09's just moved the shift points back to where they were in the plain mt82. The D4 gearing is much higher hence the need for the 4.09 change. Lots of threads discussing it.
91 is all that's available here. When I took it to Amarillo I was only able to get 90 that was the highest they had in Hereford Texas where I had to fuel up. Still no problem.
I have the same setup as Dave, I'm in the NM desert and have no access to anything e other than pump gas. I've never heard a knock or had a problem. Installed the kit at 2k mi. 4 year's ago. 4.09's at 3k. Car rocks as a daily driver. Actually my wife traded me out of it and it's her daily.