I can live with G100UL (already bought the STC), even if I have to go through the whole fuel system and R&R seals, gaskets and O-rings to reduce the likelihood of leaks and damage to paint. De-tuning and de-rating my engine so that it can run on Swift or Lyondell is unlikely to be an option for me, and would take a big chunk of the market value out of the 206 if G100UL is not readily available. In fact, it's hard to imagine why anyone other than GAMI's competitors would prefer fuels like Swift or Lyondell that require spending a lot of money to detune and derate our engines over G100UL.

If only the $70 million wasted on PAFI and EAGLE had been used to pay for G100UL STCs on the high performance SEP fleet, and to reimburse owners of high performance SEPs to replace/upgrade the seals, gaskets and O-rings in our fuel systems. All of the high performance SEPs could have been burning G100UL by now, and the rest of the fleet could be on Swift 92 or ethanol-free mogas.

My $.02

Terry/CAVU

I ran 50 gallons G100UL and I had no issues with performance other that EGT's were a bit higher and disclosed by GAMI. However, it stains, does not evaporate and it stinks. Some stains wiped clean, some required rubbing compound to remove. I have a jar of Swift 100R from SQL and the FBO is running it in their high compression C172's has no issues and it does not stain, it evaporates and smells like nail polish. I hope I never have to run G100UL ever again! I posted two PIREPS on this forum reference G100UL.

I bought the Swift "forever" STC, as well, hedging my bets. [Edit]:

Swift's FAQ, which says: "Is Swift Fuels’ 100R Unleaded Avgas “Drop-In-Ready” Fleetwide?
YES - 100R is drop-in ready across the global piston fleet. It is designed to meet global fuel requirements for piston aircraft without having to replace aircraft hardware prior to use."

I sure hope that's the case.

I run a carbureted gravity feed engine. I don't know what it would cost to "update" an entire fuel system for a different fuel, but IF all the parts were available I'd guess taking it to a shop would cost several thousand dollars. 2 fuel bladders, fuel cap gaskets, sump o rings, vent hoses, fuel selector, o rings and gaskets in the gascolator, fuel hose to transducer, fuel hose to carb, then all the "rubber" parts in the carb. Not sure how my cork on a wire fuel gauges would fair?

No thanks.

Staining, paint damage and the like? Hope you don't ever fuel a plane with a gas can, I know I spill about every time.

Just like lithium batteries, I'll let all the bugs get worked out before I join in.

Should this all come into effect I'm more likely to go the no ethanol option instead if available.

Oh, it's going to come into effect. Good, bad or indifferent. I sincerely hope that someone comes up with a 100LL substitute that actually works and doesn't cost three times what 100LL does.
Like others, I'm in a position to use 91UL and it's available here, though not currently at airports.

We'll see.