[delfinom]

https://www.g100ul.com/

>Will I have to modify my engine or aircraft to use G100UL avgas?

>Other than placards, no modifications are required. A small placard is attached to the engine and "stick-on" placards are applied to refueling ports. In addition, there is a short POH supplement added to the AFMS.

[outworlder]

Beautiful. The main sticking point was the (possible) need to re-certify existing planes. This is peanuts in comparison; probably why it took so long for such a fuel to get developed and approved.