I agree - the higher octane would be nice as a perk option.
I disagree. I have a pretty good idea of what an AH airplane can and can not do. This absolutely will effect how I engage and fly against my opponent. Giving a player an option to essentially upgrade their plane to a super version throws that out the window as I would have no idea which version they are flying.
Wide, we already have that because of icons. A F4U-1 is a big difference from a dash four.