I have repaired quite a lot of benz .
I see that you are asking for its fuel efficiency and then asking about the kompressor models, kompressor = supercharger - dont buy that car. buy a C200 with NA engine.
Before you buy it, ask yourself - if you are comfortable in affording it because these cars cannot be serviced reliably with bilal gunj parts or off brand parts like frixa, pikachu, fuji etc. My reason to say this is that almost every other person in Pakistan relies on junkyard parts to service their cars. As the japanese econo cars in Pakista are already low build quality and also used as tissue paper, it doesnt matter if you use junk on it because, its already at low quality to begin with.
It will hurt you badly if you try to do that on any german car including VW.
The model you are choosing is a bit old now and its not too hard for any sensible mechanic to sort out. To find one I would suggest dont simply trust (fallanay bhai 20 saal se shahnawaz ltd me thay) - you can follow some threads on PW to see what quality or should I say "kwaltee" of work Shahnawaz Ltd. do, they hire apprentices and keep on swapping them every few years. So its better to find someone who is sensible, has access to service literature and can understand it too, He should also have good tooling for repairs otherwise simple jobs become complex and complex jobs become tiring and tiring jobs become a money pit.