From reading some of the online "research"...it looks like a lot of the claimed benefits for MS involve diesels...high particulates for sure. For cleaner burner gas engines...maybe not so much of a gain?
Possible that higher mileage gas engines with much accumulated crud might benefit almost as much?
As for the fuel additive...I'm hoping it is at least as effective as the Techron....maybe more effective if it keeps the injectors freer. People report mpg gains from using it.
For the auto trans...maybe Lubegard has more serious recommendations behind it and from people who repair trans.
At 12 K miles/yr and $3.50/G and a 5% mpg gain...it might take me two years to recoup my costs for the MS additives. And even if there is no mpg gain...I expect some longevity gain espec for the auto trans...with all those borate esters coating the over worn steel gears.
A lot of this is conjecture....which seems to be the world I live in.
* Having reviewed the various MS sites...I have a renewed belief that I will see SOME mpg gains....though I doubt that I will be able to document them.