@@ needz!! Buddy its better to buy the car registred in teh same city, for all the right reasons!! In Karachi majority of people dont like Lahore, Islamabad, Peshawar & Quetta registered cars or even , aany car outside of Karcachi!! Being a mega city Karachi is self sufficient in used cars and people prefer to buy karachi registered cars!! One reason is that other city registered car looks "ODD MAN OUT"!! I had a freind, he bought Islamabad Registered Car few years back, he had one severe complain that "people give so much horn to my car. Then later, he realized others think that since i am from islamabad and i dont know how to drive on wide and busy roads of Karachi". To us other city registered cars have less prestigious value.
Similarly, i would recommend you to buy Islaambad registered car in Islamabad. I am sure, u are thinking to buy Karachi Registered car, just becoz u are gettign it in low price!! Here in Karachi the prices of used cars are lower than any other city, due to more demand and supply condition!!
More Checking happens in Karachi too, of other city cars!! Thus same philosophy applies for everywehre!!