The most important question: Can I use the car as intended without dealing with the vendor (Tesla)? If not => it's a service, not a product.
Not the most important question since it has nothing to do with the fleet developer API. But yes, if you are fine with not using Superchargers (which would be insane) or the built-in internet then you don't need to deal with the vendor after purchasing the car.
(No pun intended with the X)