It does exist, it has been approved by the FAA, and you can go buy the STC right now if you want[0]. The incentive is that 100LL has been banned by at least one

It does exist, it has been approved by the FAA, and you can go buy the STC right now if you want[0]. The incentive is that 100LL has been banned by at least one county[1] with states[2] trying to follow (although the AOPA successfully neutered that one[3]). [0] https://www.g100ul.com/ https://www.g100ul.com/ [1] https://www.globalair.com/articles/california-county-that-banned-100ll-to-be-first-in-faa-lead-free-transition?id=5552 https://www.globalair.com/articles/california-county-that-ba... [2] https://www.flyingmag.com/washington-bill-seeks-statewide-ban-of-100ll/hh https://www.flyingmag.com/washington-bill-seeks-statewide-ba... [3] https://www.aopa.org/news-and-media/all-news/2023/march/16/aopa-fights-back-on-washington-state-bill-banning-100ll-sales https://www.aopa.org/news-and-media/all-news/2023/march/16/a...