Nope..The instance who makes the rules is just a big bunch of assholes,that's the problem. We've also got many other rules that makes this hobby very complicated here in Finland.
If you update the brakes on your car to bigger/stronger or change the engine/gearbox they'll count the precentage of how much you've changed the car. Up to 49,9% is it allowed without paying the taxes again. When the percentage is more than 50% you have to pay the taxes.