- Five years. Been five years for a while now.
Duty structure is complex, there's a special regime for used vehicles under 1800cc, with $4000 taxes for Japanese 800cc and below, $5000 for 1000cc, $ 10000 for 1300cc, $14000 for 1500cc, $17000 for 1600cc and $21000 for 1800cc, all that is depreciated upto 50% at 2% per month given how old the car is. The only non-Japanese cars in this regime are under 800cc at $6000.
For all other cars, customs are 50/55/60/75/90% of MSRP for 801-1000/1001-1300/1301-1600/1601-1800/1801cc and above car types, depreciated on the same principle.
Restrictions are one car per person per two years, if it's a transfer of residence then you need to have spent at least 2 years abroad, and if it's personal baggage then you need to have spent at least 6 months abroad. If it's a gift, then the person needs to be of immediate blood kin, and needs to have spent 2 years abroad to send a car.
Most importers find people who've been abroad or have had relatives abroad and import cars on their name, e.g. find a mazdoor (laborer) who's been abroad, give him 10-20k and get a car shipped on his name and passport.
If you want to understand the duty structure, it's complicated and you'd need a long time to calculate all associated taxes. For easy estimates of prices on a used car that's two years old, just multiply the price by 1.3 if it's under 800cc, 1.4 if it's under 1000cc, 1.5 if it's under 1300cc, 1.6 if it's under 1600cc, 1.7 if it's under 1800cc and 1.9 if it's over 1800cc. If the car is one year old, increase the multiples by 0.1 per category, if it's a brand new car, increase them by 0.2. E.G. a brand new Accord CU2 costs $31,000, so that's 31000 x (1.9 + (.2 x 6 categories up)) = 31000 x (1.9 + (1.2)) = 31000 * 3.1 = $96,100 total cost including shipping, taxes, fees, customs, agent commissions and stuff.
Similarly a 2009 Accord CU2 worth $28,000 with cost 28000 * 1.9 = $53,200. $10,000 2009 Vitz will cost $15,000 etc.
For more details, read this document http://www.mofa.gov.pk/downloads/importofvehicles.pdf and ask further questions if you need help.