Looks like a 540c L can to me.
As for worrying about the drivetrain, my rustler has the same transmission set up/ mods as yours, and Im running 4s 5Ah lipos through an 8l with bigger, stickier (onroad) tires, with no transmission problems.
Very nice!!! I like the out-of-the-box thinking on this truck. You will not have any problems with the drivetrain. I have the exact same setup in a tube frame pede/buggy that is way heavier than yours and it holds up fine. I used jato spus and 32 pitch pinions, but that would be the only difference, and stock grey plastic trans cases.