As an owner of new and old german cars and a person who has a business of repairing such cars.
"There is no car more expensive than a cheap used german luxury sedan"
e.g. you buy a car that is and was 20,000 usd brand new - its maintenance will be of a 20K car (corolla/civic etc etc) - if you buy a bargain priced used luxury car for 20,000 USD and its original price was 70,000 USD - it will still have maintenance costs of a 70K USD car.
Another problem is that people dont maintain these cars in Pakistan because of their expense and also because of their moronic beliefs of "jurmann gaddi mazboot gaddi aye" - and literally proceed to drive a clapped out piece of scrap with howling bearings, slamming transmission, bucking engine, non working electrics but hey - its a lux symbol.
TL DR
stick to what you can afford to own, not afford to buy.