I actually doubt that smog (at least in CA) would be done wirelessly, as the bureaucrats would want to see the car. Otherwise, you could have a Prius with a 400 hp V-8 with no smog equipment shoehorned in back for all they know. Stock drivetrain would be 100% intact, of course.
Or for that matter a mobile app that’s pretending to be a car to the bureaucrats’ computers 🙂
Also: does CA do physical inspections for things like brake pads, tires, steering, and lights?