Nintendo revealed the first three "Coin Rush" DLC packs for New Super Mario Bros. 2 in a Japanese Nintendo Direct episode that aired yesterday. The DLC adds new levels to the game, including more gold coin challenges and what appears to be some very tough new levels. The full video feed is below.
The first pack is called the "Go! Go! As Gold Mario Pack," which includes the three levels that encourage you to turn everything in sight into gold coins. "Challenge the Record! A Pack" is a specific set of levels with an online leaderboard. "Survival Panic Pack" is the set of hard levels which should greatly interest players who want a challenge.
The DLC releases in Japan on October 2nd for 200 yen each. Other regions will likely have it soon after that.