Assuming that you're talking about a US based 300 C with the REC navigation system (i.e. not the MyGig system), then any of the discs mentioned should work, the AF is simply the most up-to-date version. AE is the version before the AF. The hacked version that people refer to is a version that has been altered so that you can access the navigation menu features while the car is in motion. The hacked AF is the version I'd get. As for "RDS," that's something unrelated to the navigation portion of your unit. It's the feature that displays the station name, song title and artist on the screen when you're listening to the radio.