We take our Audi to Porsche Sarajevo Service (they handle several other car brands as well). It’s located a bit outside the city—about 12 km from the center. You can book an appointment online, but the system is only in Bosnian, so using Google Translate is a must.
While the service center is generally well organized, it’s a good idea to double-check all the details when booking and upon arrival. In our experience, a few things were accidentally left out of our appointment, and once the work wasn’t completed properly, which meant returning multiple times. Also worth noting, it’s not the most budget-friendly option.