So this one time I heard Superman talk about what he was wearing as his "uniform". And I can sort of understand where he was coming from: it is recognisable, and he wears it all the time; it's basically his work clothes. But it's clearly not a uniform. A uniform is something that a group of people wears, like an army or a team, and it gives them a uniform appearance. Hence the name. That said, I can see that calling it a "costume" (which used to be pretty much the industry standard word) really gives the impression that you're just playing dress-up. I don't know what the kids are calling them these days.

Note to subconscious: No, "Hoot and Holla" is not a good name for a duo of superpowered crime-fighting owls

Additional: No that is not supposed to be any specific kind of car.