Which cars can use a scanguage or super-mid?

[DracoFelis]

I think I've finally gotten to the tipping point, where I want to consider buying/installing real time FE (and other car status info) feedback in the two cars we drive the most (i.e. mine and my wife's main "commuter cars"). However, I would hate to spend the money on a scanguage and/or super-mid, only to find it won't work in our case.

So how can you easily tell (before buying it and trying) if a given vehicle can take a scanguage and/or super-mid?

As I understand it, almost all newer vehicles (sold in the USA) can take a scanguage, as there is supposedly a law on the books that car makers have to provide the standard computer interface that the scanguage requires. Is this correct? If so, when was the cutoff date requiring the car makers to do this?

Also, even if that is the case, how can you tell if an older car has the correct interface to take a scanguage? Is it as simple as looking at the car, to see if it has a given shape interface jack present (and if so, what does the jack you are looking for look like)? If not, is there any other "easy way" to tell if a scanguage would work?

And what about the super-mid? My understanding (again, correct me if I'm wrong) is that the super-mid will work in some vehicles that the scanguage won't work in, but that it can be more of a PITA (than the scanguage) to install initially. However, if that's true, how do you tell if your car can take a super-mid (which would be especially important to those of us who have older cars that might not be able to take a scanguage)? Also, how can you tell how much work it will be to hook a super-mid up to your car (assuming your car can even take a super-mid)?