Pretty sure they don't sell the front bumper on its own, you have to get the entire kit.
1. BMW Performance X6 Aero Kit. Part No. 51192162471
2. Performance Black Grill. Part Nos: 5171250247 (Left) 5171250246 (Right)
More info here:
http://parts.bmwofsouthatlanta.com/s...ssembly=422033