The computer is tiny, so I don't know if they use some... low profile cards or what. I can't really tell. It might not be easily upgradeable, but why buy something mediocre now and spend more money upgrading it in the future? The 999 option is the minimum you would need for a GOOD gaming experience.
Honestly, with a budget that high it would be foolish not to build your own. It literally takes a couple hours at most to build a computer, and you have much much better parts that will last longer and perform better.