Ahead of its official unveiling at the Geneva Auto Show, McLaren releases details regarding its P1 GTR supercar. Based on McLaren’s million-dollar flagship model, the GTR ‘skirts’ pass with a long list of upgrades that make it better suited for a closed circuit than local roads. The 3.8-liter twin-turbo V8 hybrid powertrain features an internal combustion engine cranking out 789 horsepower and an electric motor adding another 197 for a combined output of 986 hp. To optimize the power-to-weight ratio, the automaker introduced a carbon fiber roof and engine cover, plexiglass side windows, and a new Inconel and titanium alloy exhaust, all of which results in a 110-pound reduction. Although 0-60 times and top speeds have yet to be published, you can head over to Autoblog to read the official press release.