earlwb

I believe that Citgo is the parent company for the Mystik line of lubricants. Thus Citgo makes the oils and grease that Mystik sells under their brand.
Of course the rumor has it that Castrol is the company that makes the special oils that Stihl sells under their brand too. A private specialty blender mixes it for Stihl here in the USA.

My concern is that it will be like Amsoil where all of the testimonials seem to be from dealers who sell the stuff. But I am not above not trying the Mystik brand stuff though. The real trick is how well the stuff protects the engine after a few gallons of fuel have been run through it. Unfortunately, I don't have an engine I would care to risk with the stuff at this time. I am currently running my engines with Stihl oil for a few gallons to see how much carbon or less carbon deposits there are in comparison with the Amsoil oil I was using. But maybe later I will.

Stihl did run some 100 hour engine test runs and their oil did pretty good actually. Model airplane engines tend to be run pretty hard as people tend to fly them full throttle all of the time and that is really hard on a model engine to be under a full load and full throttle like that. Then you have the 3D aerobatic guys who like to hover a lot, and fly at lower throttle settings, but they still tend to thrash their engines hard too. Of course the RC helicopter guys run their engines really hard at a fixed high RPM setting too.

Does Mystick have any pictures of the insides of air cooled two stroke engines after a 100 hours of runtime yet? That would be really interesting to see. They might have something there. I am interested in how much carbon build up and residue there is left over inside of the engine, and what the piston and rings look like.