I just opened up one of my Christmas presents which happened to be a brand new copy of Forza Motorsport 3 Ultimate Collection. Disc #2 installed without a hitch, but there was an add-in DLC card that contains 3 items: Stig’s Garage Car Pack, Top Gear Video and Top Gear/Forza Premium Theme. I attempted to redeem the Stig’s Garage Car Pack, but even though I am inputting the code correctly, it says that it is an invalid code. Any ideas as to why this is happening?
Because all the DLC for FM3 has been removed from the marketplace which means you cannot get it anymore. For more info visit this thread - at the end of the day the disc you have received may have never been used but was actually pressed several years ago.