1) Buy the car, (Preferable from person who is in Karachi, since his presence is required for biometrics ) (If Smart card issued), Come to Karachi, and transfer it on your name, and do biometrics etc.
2) And if the car owner is using car on Book, (If Smart card not issued), Then just buy the car, come to khi when you are free (Owner not needed), transfer it to your name.