I just saw this on Wired and thought it was very interesting. Using off-the-shelf technology, Corvette Racing installed a rear-facing camera and radar system that can actually categorize cars as Prototype or GT and label them with color-coded chevrons that give the driver an idea of their closing speed, what side they are passing on, etc. They used it on the number 4 car during the 12 Hours of Sebring.
http://www.wired.com/autopia/2013/03/corvette-racer-radar/
Do you think it will eventually make it to other cars/racing series, or will it be banned?