Hi Peter,
Here is a great article about importing cars:
Costa Rica Customs for VehiclesIf you understand a bit of Spanish, you can check here for the duties on exact makes and models:
Costa Rica HaciendaFor a rough estimate, it comes down to the "Vehicle's Customs Appraised Value", which is a combination of the Black Book Value, the frieght cost, and insurance value.
A car less than 3 years old pays 59.33%, a car 4-5 years pays 70.63% and a car over 6 years old pays 85.32%
It is vital to work with a reliable freight forwarder.
That said, it is my humble opinion that you would do better to purchase a car locally from a reliable used car dealer for these reasons
- Due to excessive competition the importer's margins are very low. I have done calculations and the price you pay a dealer is almost the same as you would pay importing yourself, or even less.
- They offer a 30 day guarantee on the motor and transmission (mandated by law)
- They will help you register the car in the national registry, often included in the price.
- You save the time and expense of the importation process.
You can see some cars online here:
Autos Usados Costa Rica 
