What looks right for a track version: The suspension is clearly lowered and the tires are race-friendly single lug units (not to mention the massive carbon brakes). Also, we've got some flared side skirts and, clear as day, hood pins. Another hint, via Autoblog:
One thing we do know: The launch of the 599 GTO is going on this week in Italy, so it's likely that journalists are getting a sneak peek at the Challenge between making runs in Ferrari's Enzo-beating GT. That being the case, expect all the details to be revealed shortly.

This is a very cool thing indeed -- especially since, short of stalking some power broker in Beverly Hills, a track version of the 458 Italia will give me the most viewing pleasure of a truly remarkable machine.