Yes you can import Japanese cars.
No, it's not necessary the imported car be less expensive than ones available here.
Price depends on grade of the car being imported.
Different grades different problems for example : small dents to major accidental cars.
According to Law of Pakistan only 3 years old cars are allowed to be imported. @sharabhi is the used Japanese car dealer here, a very trusted person. @capsat can provide you more info on Shahzeb.
At the end you are only calculating the price of car and shipping cost. The actual price includes price of car, shipping cost, custom charges, agent charges, registration cost etc.