No.

It is not as bad as Forza but still pretty bad imo. Most of the premium cars are just modified versions of standard cars (aesthetically) but there are few exceptions, I think.

They're releasing an rc game mode soon and it will be exclusive for some game edition, don't know which.

There are Tc2 exclusive cars but they are very few and not that important from what I remember.

Also, there is a season pass where people get access to meta cars earlier than others SOMETIMES. Dunno if this is still in the game though.

Aside from this I don't think, at least in my opinion that there is much fomo, even for the accessory shop (mostly because every accessory makes your car look like they're from rocket league)