Comment by yesyes

What hoops? If the purchaser wants to install a stereo he can choose to do it himself or take the car to a shop that installs stereos. What's happening in this case is, roughly, by analogy, the car manufacturer is trying to exercise control over a shop that is selling stereos that can be installed in the car. Is that overreaching? Would consumers complain if a car manufacturer actually tried to do that? The factory installed stereo better be very good.