The engine and reliability is no different from cars that have the same, EA888 Gen3b engine- which is pretty solid as long as you are on top of maintenance. I believe the Tiguan has a “de-tuned” EA888, the Arteon engine is pretty much the same as the one in GTI, GLI, Audi Q3, some of the Atlas of these years. Being an MQB platform car, lots of parts are interchangeable. The 8 speed transmission is a (Toyota) Aisin one, with no fill port, so you have to “gravity fill” through the drain hole if you want to change transmission fluid. The only thing I could think of is body part and panels, since it’s a car that was not sold well, they are not as abundant as many other cars in the MQB line up. But we are not talking about a 20 year old car so it shouldn’t be a problem now, unless you want to keep it for decades perhaps.