Kotaku
Lots of new stuff making its way into Gears of War on the PC. Extra missions, shinier graphics, the Brumak...all new. And all PC-only, with none of it planned to be making its way to the 360. Gears PC producer and former lumberjacking world champion Rod Fergusson:
There is no plan to provide the PC exclusive content to Xbox 360 gamers for a number of technical reasons. One is simply the size and scope of the new content which would be difficult to deliver as an update. But more importantly, Gears of War for Windows was not created with the same version of Unreal Engine 3 as Gears of War for 360. We wanted to take advantage of all the latest and greatest optimizations and features that are constantly being added to UE3 and as such, this new content is not easily compatible with the Xbox 360 version.Kinda sucks for 360 owners, but hey, you did get it nearly a year earlier. You can't have your Gears cake and eat it too.
No Gears of War Expansion for 360 [IGN]
