On the whole Sales thing... And bundle talk.
Forza 3 was bundled on release - http://www.eurogamer.net/articles/250gb-forza-3-xbox-360-unveiled
It recieved a bundle around March/April 2010, with Halo: ODST - http://www.1up.com/news/forza-3halo-3-odst-bundle
It recieved another bundle in November 2010 too, with Alan Wake - http://www.crunchgear.com/2010/11/02/250gb-xbox-360-holiday-bundle-includes-forza-3-alan-wake/
I think these are the only official bundles for the game... But sales as of each bundle were -
Bundle 1 - 0
Bundle 2 - 2.33M (The Week this bundle was introduced, sales went from sub-24k to 40k/60k/45k... Then hovering around 30/40k, until the bundle was stopped and it dropped out of the charts again selling sub-20k. Added ~450k)
Bundle 3 - ~3.1M (This bundle was the Holiday bundle, and added almost 1.5M units onto Forza 3 total)
So, yeah. It was bundled on release, a few Months after release, and a Year after release. Despite these bundles, it was outsold by GT5 (According to VGC), after 5 Weeks of being on sale. About 2 Million of F3's 4.8M units came from Bundles. That's a huge number...
Expecting it to do GT-like numbers, when the series hasn't broke 5 Million yet despite massive bundling, advertising and lack of meaningful competition on release... Is IMO silly.
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As for The Stig being in Forza, awesome! Everybody loves The Stig.