(Aero) "body kits" are now legal in IndyCar. The idea, when mooted a few years ago, was to make the cars look different from each other--as in the Good Old Days. (My good old days were 1980's, when almost everyone was running March or Lola road racing-capable chassis which looked pretty-much the same). The differences are minor and doubtless hemmed-in by overall dimensional rules. And the body kits are homologated by IndyCar, paired with, and tested by, each engine manufacturer. I didn't think it was possible to make an IndyCar any uglier than it already was. It is.
But it was fun, and pretty, to watch them tippy-toe around in the rain in qualifying at New Orleans. It's not often that IndyCar drivers are heard feathering the throttle multiple times in multiple corners. Even with massive downforce, rain brings driver talent and car control to the fore.