Jonny Lieberman and Randy Pobst examine two of the highest performing vehicles on sale today, and they’re both called GT-Rs. Or is that GT Rs? From Nissan comes the Nismo version of its long-running supercar. Power is unchanged for 2017—still a healthy 600 hp—but structurally, the body in white has been strengthened. This seemingly simple change pays huge dividends in terms of overall performance and is in line with Nissan’s mantra of gradual improvement. The AMG GT R, on the other hand, is pretty radical compared to the regular-strength GT S. Power is way up, the front and rear tracks are wider, the torque tube is carbon fiber, the gears in the twin clutch are different, the body is flared, and the exhaust, front splitter, side skirts, and carbon-fiber rear wing are brand-new. Let’s not forget the four-wheel steering. Each of these monsters was created to do damage to the Nürburgring, but how will they do in the twisted canyons of Southern California, as well as a slightly less formidable racetrack? Watch and find out!