During this year’s Goodwood Festival of Speed, Mercedes-AMG unveiled the newest member of its AMG GT family — the AMG GT-R. The latest weapon in Mercedes’ arsenal takes what it’s learned from the road-going GT and GT-S coupes and race-ready GT3 and brings it all together.The hand-built DOHC 4.0-liter twin-turbocharged V8 powering the GT-R sits in same mid-front position as the rest of the GT lineup, but churns out 74 hp more than the current top-performing GT-S. This bump brings the GT-R’s total output to 577 hp. The two turbos spool to a maximum speed of 186,000 revolutions a minute and stop building boost at 19.6 psi. That air is then rushed through liquid-to-air intercoolers before it’s stuffed into the engine.All those ponies go to the rear 20-inch lightweight aluminum wheels by way of a seven-speed dual clutch transaxle. Nestled inside the transaxle is also a much-needed limited slip differential.http://www.marketwatch.com/story/this-new-mercedes...