Well I also think it depends on the car you are getting. According to a FICO change in approvals have bumped up the required FICO scores for certain vehicles. Although GM has announced this apr range but they don't specify a required score. Here's another link to mulitple manufacturers that are offering that apr range.
Best of luck, I surely couldn't get those scores anyway!
If you read the fine print on most ads they always have something like 750+ Fico but the super low APR's are usually for 3yrs or less so payments are going to be super high.