Honestly, my understanding is that the differences between the various version of Car Simulator is largely academic...until mods.I have 2014 (or is it 2015?) and I enjoyed it for several hours....once I got fast unscrew. If you stick to it until you have all the 'fast' tools you'll find it can be a very relaxing and zen game.
2018 is on my "Steam Sale" list, but I have so many other games I'm trying to play it isn't on my "must buy as soon as I can" list.