The 599 GTO, the third Fezza to wear the Gran Turismo Omologato moniker (the iconic and crazy-valuable 250 GTO of the ‘60s and the mid-engine 288 GTO of the ‘80s being the others), sees the Enzo-based 6.0L V12 bumped up to 661hp and 457 lb.-ft of torque, gains of 49 and 9, respectively, over the standard 599 GTB Fiorano.