American tuning workshop Hennessey Performance is renowned for its work with the Dodge Viper, but the firm has also reworked the formidable Nissan GT-R in the past--taking it beyond supercar performance and up into the hypercar arena. The Texas-based tuner currently offers several levels of tune for the GT-R, ranging from about 600 all the way up to 800 horsepower.

While that latter figure may prove a bit too extreme for most drivers, Hennessey is now offering a new kit dubbed the GTR650, which offers a much more sane 662 horsepower and torque to 638 pound-feet. Remember, the stock 2012 Nissan GT-R with 523 horsepower will do 0-60 mph in 3.0 seconds flat so imagine with an extra 140 horses will do.

These figures are achieved through a number of upgrades to the GT-R's induction and exhaust systems, an upgraded boost controller and new intercoolers but importantly, the stock turbochargers remain.

Other modifications customers can select from include a premium wheel and tire package, KW adjustable coil-over shocks, an uprated clutch pack, carbon fiber body components and a Sumo electronic exhaust cutout. Additionally, Hennessey is also offering performance parts from some rival brands such as HKS, Cobb and Zele.