This is the biggest concern that I have; i.e. compatibility. I am at an airport that has banned 100LL and my engine cannot legally use UL94. My initial review of the known contents of G100UL suggest that there is healthy skepticism in the area of long term compatibility. Why are other fuel providers avoiding utilizing similar compositions (aside from patent issues)? And then there’s the fact that I have to have yet another major alteration (STC) to use a specific fuel. All of this just gets complex…