Ok, this is not actually the Hennessy Cognac, although the owner of a particular GTR might think he really do have 600hp after a few shots of Hennessy, this is actually Hennessy Performance, an American tuner famous for creating outrageously powerful tuning packages for cars like Dodge Viper and so on. They've revealed their 'little' upgrades which includes:
Air Induction System Upgrade
Electronic Boost Controller
Stainless Steel Turbo Down PipesStainless Steel Mid-Pipe Exhaust Upgrade
Stainless Steel Rear Section Exhaust Upgrade
Wastegate Actuator Upgrade
Front Mount Intercooler System Upgrade
And all those actually brings an additional 120hp, bringing total output to 600hp for the GTR. Who would want the 520hp V-Spec that costs almost twice the price of a regular GTR?
Source: Hennessy
