The Q45 is a rear-wheel-drive sedan powered by a 4.5-liter twin-cam V8. This all-aluminum engine produces a very healthy 340 horsepower and 333 pound-feet of torque. The only available transmission is a five-speed automatic with a manual shift mode. It comes in two trim levels: base and Sport. The base includes everything you'd expect in a flagship luxury car, plus a long list of high-end electronics. The Sport model gains 19-inch wheels, a better suspension, and Rear Active Steer.For 2006, the INFINITI Q45 comes in a new Sport model.