Hi
If you didn't know and most likely a lot of peoples dont even know about this the "Terromania' dlc can only be bought from ingame store using Rage 2 coins and this is an online store which means if anything happens sadly that dlc will be become unobatainable even if you own the base game.
So its a good idea to grab this dlc which costs only 500 coins equals to $5 US, Of course thats what you need for the achievements but if you prefer to get everything available you have to buy the "Terrormania Digital Deluxe Upgrade" which gives you this dlc and more stuff and it costs 1750 coins equals to $17.50 US.
In the end just wanted to warn more peoples about this small detail about this dlc so they don't get screwed if something goes wrong with the in-game store.
You can read more about this here:
https://www.gamewatcher.com/news/rage-2-terrormania-digital-...Crysis Regards