That depends on what are the parts to be serviced each time. I would say in average about RM600-1000. Labour cost is expensive though. About service charge I was once very worried too as many people said expensive in the forum, but once you are in it and you are going through it, it is ok. My friend is driving a C250, his service is more expensive in general compared to mine, and his car had already repaired 3,4 times. Anyway, I can't guarantee any car is perfect as this is the qc problem, let's be safe to say regardless proton, BMW, or Perodua, it is really depend on your "luck".