Yes, it sure is a rare beauty since there aren't many in Pakistan and there are handful of 540s here. Maintaining isn't really hard since I've got my relatives living in KSA, UK and the US, so getting the parts isn't a problem at all, about the labor, it's a simple myth that the pros are ready to work for you if you're paying them the money that they'd expect from a guy owning a BMW 
Everything's available in Pakistan, you just need to find the right people for the job, this car is already maintained by INH previously.