I said whatever PS3 game vs SMG, but OK, let's do FFXIII if you really want.
So the bet is: First 3 months of SMG outsell first 3 months of FFXIII worldwide.
(3 million in Japan alone, they will have to sell over 1 million consoles in Japan this year AND have a 100% attach rate. The first part could well be possible, the second not.)