You can easily find all the info about your queries here on pw.
The only thing i want to metion is that a diesel supercharged engine, like these germans have, a big disaster in Pakistan. You cant find good diesel anywhere in Pakistan. If someone claims that he sells or buy clean diesel from sulphur lead etc. I want to meet him.
So no option for a diesel. If you ever bought such thing. You will remember my words for ever.
I even saw many vehicle under 100k km garaged for engine overhauls. Injectors etc problems. A high pressure common rail engine maintenance in Pakistan is also a problem. No one is that professional to maintain.
A good german diesel powered vehicle will last about 1000k km but abroad where they get clean diesel. In Pak they hardly last for 100k km.
I personally driven 520d, it feels like a 4000cc vehicle but not wise to buy here.