Cars inherit from WheeledVehiclePawn, which has a ChaosWheeledVehicleMovementComponent with all sorts of stats that are class defaults and setters for a (too) small subset of them. I don’t immediately see a way to expose variables as public via blueprint when they are private in the component you are forced to use. 
Am I missing something?
I was hoping to avoid having to dive into the C++ source files and figure out how to change some class defaults (which I’m assuming are static properties) to instanced variables, but it may be the only option.
Oh well, let’s bite the bullet and learn some C++ then…