There are 2 downloads that have just been released for PGR4. The FREE one, which includes a concept car and 2 new games modes will also net you 10 new achievements. The Premium content, which will cost 400 points, includes 7 new cars and a new World Challenge mode which in itself includes 20 new events. Hit the jump for the full descriptions.

[via Majornelson]

Content: Free Challenge Pack
Price: Free
Availability: All Xbox LIVE regions

Download the new Free PGR 4 Challenge Pack from Bizarre, and you’ll drive the hydrogen-powered 2007 Peugeot Flux, winner of the 2007 Peugeot International Design Competition. Plus, you’ll get two new game modes—one of them the player-requested Tourist Mode, which lets you tool around any city in the game checking out sights with your friends. Or play Free Roam Cat and Mouse, where a slow mouse vehicle must avoid enemy cats. And you add another 10 achievements. Get more racing fun for the best price—free!

Content: Premium Challenge Pack
Price: 400 Microsoft Points
Availability: All regions

The Premium PGR 4 Challenge Pack from Bizarre, available for 400 Microsoft® Points, gives you seven new cars—the 2008 Chevrolet Camaro Convertible Concept, 2007 Volkswagen Golf GTI W12-650, 2007 Peugeot Flux, 1987 BMW M3 E30 DTM, 2007 Ferrari 430 Scuderia, 2008 Honda S2000 CR, and 2008 Callaway C16 Speedster. You get three new bikes—the 2007 Yamaha YZF-R1, 1995 Aprilia RS 250, and 1998 Aprilia RSV 1000 Tuono R. Plus, new World Challenge Arcade Mode gives you 20 arcade events in 3 themed chapters, including 5 events that can only be done on platinum. In Tourist Mode, get a free ride with friends around any game city. In Free Roam Cat and Mouse, a slow mouse vehicle runs from enemy cats. Ten new achievements fill out the pack. There are no refunds for this item. For more information, see www.xbox.com/live/accounts.