Halo: Reach sold at least 1 million sales digitally as it was bundled with Fable 3 which sold 1.5m during the 2011 holidays. Realistically it sold 1.5-1.75 million digitally which will put it at about 11-11.2 million.
I don't think GT5 will outsell Halo: Reach until the end of next year, unless GT6 kills its legs and it stops at around 11.25m and Halo: Reach will be a tiny amount in front. They will be ridiculously close in the end I think, wish we had hard numbers on Halo: Reaches digital sales.