This is the Kia K9, Kia’s first rear-drive flagship for North America. Kia has previously sold a rebadged Mazda 929 in Korea but those days are mercifully over.
Someone in South Korea took a couple videos of the K9 driving along a highway. You can peruse them for yourself below. The K9 will probably shed its alphanumeric moniker when it arrives in 2013.