If these stuck on there screens, don't work as you would like them, with what else you can replace with? Nothing, you are stuck with it, until you own the vehicle. They have proprietary connectors, much harder to connect other aftermarket stuff to them as well.
I guess, when you are in the process of buying the car, you really have to sit down and test all of the features that has, to be sure that you are OK with them. But what if, later on you upgrade your phone and it doesn't work as before?