Well you can find RHD vehicles in Kabul and definatly in Herat. I personally have seen many RHD corolla's on the road. And its not necessary that you shall register them in Kabul, it can be done any where.
As per my calculation, the cost should be following for a 1599CC car.
Purchase price: say $7,000
Full duty on engine capacity: $10,000
Rebate on duty for deprciation: say 30% $3,000
So total cost will be $14,000 (7+10-3), equal to Rs 850,000, which i think for a Japan assemble fully powered coralla is not a bad price. However, if still i have to pay any kickbacks to custom authorities, then the story is different.
Voyager- Can you please tell me why Pak Embassy discouraged you from importing vehicle from here ?