https://www.worldofmods.com/beamng/cars/397-porsche-911.html I don't think it can be found through any legit sources anymore.
The 49 Cad' mod is deleted for some reason. The oldest mod in here is made by dkutch, I think it's this one. https://www.beamng.com/threads/2004-campbell-moonbuggy-updated.1217/ But please don't bump the thread.
The 1949 Cadillac is the oldest mod on the forums, but it has since been deleted. You can try searching on Google for a link, but there isn't much of a chance to find it.
number 1 that was really funny I actually enjoyed that number 2 I know I tried but they aren't the actual mod they are an application, just a virus waiting to happen