While the 2006 Infiniti Q45 Sport’s 340 horsepower and 333 lb.-ft. of torque may sound substantial, the 4,154-lb. curb weight is a lot of heft to motivate. Off the line acceleration is impressive, but the Q45 Sport has a tendency to feel a bit overweight and underpowered, especially when compared with other V8-powered premium sedans.

The Sport model carries a 67-lb. weight penalty over the base Q45, yet it offers a slightly improved weight distribution. Sport models carry 53 percent of the curb weight up front and 47 percent in the rear, whereas base Q45’s carry 56 percent up front and 46 percent over the rear drive wheels.