Tram,
You do not need a STC if you want to use mogas.
This does not absolve you of your responsibility to make sure that your engine will be happy with mogas.
For starters, you need to know what the compression ratio is on your engine.
Any ratio below 8:5 to 1 appears to do well for people running mogas.
A cool running fuel system is required to keep your vapor lock issues in check.
An injected system is in your favor due to higher fuel pressure and the much lower threshold for the potential onset of vapor lock.
Running 100LL in one tank and mogas in the other is a very good way to test
your system before you go all out on mogas only.
Mogas with or without ethanol works well for hundreds of users.
Price difference is significant, today's price at CCR for 100LL 4.90 vs 2.20 for
91Octane E10. There is almost always a $2 spread and don't think cheap gas is back for good.
Before you invest in a fuel transport set up, consider 5 gal cans.
Fill up 3 or 4 to top off your tank and store none of the auto fuel in your hangar. You want mogas to be as fresh as it can be and besides as many
have pointed out, storing gas in your hangar may be frowned upon by authorities.
A 5 gallon can empties into your tank in less than 1 minute even through a filter/funnel and is easy to lift.
Lastly, take advice from people with lots of mogas experience.
You can look forward to a cleaner running engine without lead contamination and deposits on your spark plugs
