No, they're not going to pay anyone to play a videogame to make sure the downforce settings the game designer chose are perfectly aligned with the real-life settings on an antique race car that Sauber built in 1989 (MB owns the rights to the car and supplied the engine, but Sauber was the actual constructor).
I dont think you have a very comprehensive understanding of how licensing agreements work
This is meant as no offense of course.
Every car that is released in AC (or other games where the content is licensed)... gets sent to the respective manufacturer before it releases to the public for approval. So yes, Merc, Porsche, BMW, Ford, etc all have teams that go over the content before it releases just for the explicit purpose of verifying that the content is as true of a representation to the actual product that the sim can faithfully represent.
It should be noted that this isnt always people directly from the manufacturer. Manu's commonly have 3rd party companies take care of all the licensing stuff. And these 3rd party companies are then the ones that Kunos, Sector3, Reiza, etc have to deal with to license a car. So these 3rd party companies are the ones giving approval and making sure that the cars are as faithful a representation as the license agreement calls for. And this is at the behest of the manufacturers for whose cars they license. This isnt always the case, but it happens often enough to mention.
So, if Kunos, Sector3, ISI, etc wanted to release a different version of the car, they would send it to the manufacturer for approval before releasing it, unless they want to damage their relationship with the company for doing 1) something against the license agreement 2) releasing a piece of content that the manufacturer doesnt want to be released.
Beyond that, I completely agree that it would have been nice to have the sprint version from the get-go. However, that is not what happened for reasons already stated numerous times.
And frankly, I think you may be a bit beyond help here when you have been told, in explicit terms twice now from 2 devs that work for Kunos (the main physics guy and the car content manager I believe) exactly why the sprint version isnt included.
So, for one final time...
The Mercedes C9 Sprint version is not included in Assetto Corsa due to:
1: being part of a licence limitation - which are understandably and traditionally undisclosed for mere players of the game - that somehow prevents developers from including any modifications of the original car for which they originally obtained the licence in the first place.
2: said developer upon gauging the sheer breadth of chaos, disruption and mayhem such misjudged omission could potentially cause in our beloved simracing community, literally affecting the lives of tens of people, decided to deliberately and purposefully leave out the aforementioned vehicle because THEY JUST WANT TO WATCH THE WORLD BURN!
And you can figure out which of those 2 is not the actual answer.
This thread has been going nowhere for a while now.
/thread