I was researching this yesterday actually. There is a guy on the Corvette sites and his LS3 has no issues and is tuned to take advantage of the higher octane. +40 rwhp. The fuel system apparently has no problems with it, just the computer is not able to switch back and forth in stock form like other GM engines.
http://forums.corvetteforum.com/c6-t...e-ls3-mnl.html