Korea is emerging as a key test bed for the global chauffeur-driven luxury vehicle market, as Mercedes-Benz, BMW and Genesis prepare to go head-to-head with flagship models targeting corporate executives and business owners. The competition is set to intensify in the second half of this year with the launch of the Genesis GV90, the latest Mercedes-Benz S-Class and BMW's 7 Series. The luxury lineup reflects a major shift in Korea's automotive mar…