Good luck to GM with this one.
Excuse me while I stop smirking.
The Koreans have one of the most - perhaps
the most - restricted markets in the developed world. They use any and all methods to deter foreign penetration.
Not sure if this classic is still being used, but here goes: buyers of imported cars are (or were) singled out for a special tax audit by the local tax inspectors.
Or try this one: dealers in imported cars are (or were) allocated crappy backstreet lots well away from main dealership traffic and are limited to a certain size (i.e X square meters only).
The South Koreans are not a stupid people. Far, far from it. Their government is far more shrewd and nationalistic than the naive free-market, open-borders crowd who mismanage America and Europe and their rapidly dying industrial bases.
As a matter of interest, check out how many Japanese cars are (or aren't) sold in South Korea.
These people are very, very smart.