This isn't a rumor because Nissan even confirmed it.
Don't think for a moment that tree-loving, bike riding hippies have won. Just because the next-generation Nissan GT-R, due in around 2015, is going to feature a hybrid powertrain doesn't mean it's going soft on performance. In fact, it's going to be the exact opposite. Nissan exec Andy Palmer has not only confirmed what we've long suspected, but that the use of electrification to boost performance will actually make it more powerful than the current R35.
The electric systems can fill in the gaps in the torque curve and offer genuine performance gains, as well as lowering emissions. It's a win-win, and I'd expect to see some form of hybridization on the next generation car," Palmer recently stated. So if the current GT-R produces 545 horsepower and 463 lb-ft of torque thanks to its twin-turbo 3.8-liter V6, then it'd be fair to expect the R36 to have an output of at least 600 hp. If you recall, the new Porsche 918 Spyder has 608 hp and 389 lb-ft. Point being, Nissan is making the smart powertrain decision here.