I bet Forza 4 will outsell Gran Turismo 5 in Americas.

[ElGranCabeza]

Forza 3 was also 40 bucks 2 weeks after it released on all major retailers and so was L4D2, I remember because I snatched up L4D2 quickly. MS must've made a deal with retailers in order to get more awareness to those two franchises and that's probably how they kept L4D exclusive to the 360.