Thanks for the info
We only have limited variety of cars made locally, so there's a good reason to import. The import tariffs also aren't so high as to make imports unattractive. South Korea is different on the first count - from my impressions, they have lots of domestics there, like in the Japanese domestic market (markets outside of Japan only get a part of what they offer domestically). The variety of cars is such that they really have something to suit most people.
I'm not sure about the taxes, but that may or may not also be a factor.
This all comes back to the fact that people don't buy many imports in Korea, so the numbers aren't that telling, and even less so considering the entry prices of the brands in question.