Last year, Fuqua specifically stated that business casual was okay. I think some people thought that was somewhat of a trick (it was not) and still wore a suit. Some people feel more comfortable in suits, others do not. If the guidelines are the same this year, then do what you feel is more comfortable. You won't look out of place in one, you won't look out of place not in one.
As far as having a rental car, I think it's more a convenience factor. It will likely you cost you the same (could even be cheaper) as a taxi.