Two new packs of content went up on Xbox Live today for Project Gotham Racing 4 per Major Nelson. The Free Challenge Pack is a free download and includes the hydrogen-powered 2007 Peugeot Flux (Hey, wasn't the Hindenburg hydrogen powered?), two new game modes (Tourist Mode for free ride and Free Roam Cat and Mouse). In addition, another 10 achievements are also available.

The second piece of DLC is the Premium Challenge Pack (400 points), which gets you seven new cars, three new bikes and another new event (Challenge Arcade Mode and its 20 new arcade events). It appears that all aspects of the Free Challenge Pack are found in the Premium Challenge Pack.