So Deluxe mostly just gets you an extra car pack or two and the VIP membership, which is for bonus XP/prize money in events and some unique gear/liveries/etc. I generally don't bother with it.
The Ultimate Edition gets you all the Season 1 car expansion stuff, but the base game has 700 cars and the 32 (+?) tracks, so I think you're safe just going Standard. Unless you're a little neurotic about having a complete [whatever], because as the DLC season moves on, you'll see those DLC cars in the store with a little "DLC" icon. It's never felt disruptive in the past, and they've generally given select free DLC cars anyway to standard players.
I just went Standard, personally. There's a lot of game here.