heads up to those that travel and bring their games and game saves...
forza 3 deletes dlc cars if you load your save game on someone else's 360!
long story short, over thanksgiving break i brought f3 and my hdd to my parents so i could get some raciong done up there on my pops 360. i swap my hdd for his, load the game, and a message popped up telling me that i had dlc cars in my garage that would be deleted. i assumed this meant while playing on this xbox (something about digital content rights and my 360 hdd not recognizing his 360...), not permanently. i was wrong. thankfully, all i lost was my classic race tuned fiat, but still, thats in game credits i lost in its purchase and the purchase of the parts, and time spent tuning, etc.
this could be potentially much more harmful to those of you that have paid for the dlc car packs though, so take note.