The A45 AMG has 'only' 355 horsepower but it is underrated. It also is mated to an all wheel drive drivetrain with a 7-speed dual clutch transmission versus the automatic in the E63 AMG. The M133 2.0 liter turbocharged motor is proving potent as our friends in Australia showed the platform is powering the A45/CLA45 AMG to 12 second 1/4 mile runs in the ~110 trap speed range.
So how does little brother do versus its big brother? Check out how CAR did pitting the vehicles against each other in a drag race below.
P.S. CAR, a drag race without trap speeds is only telling part of the picture. You're professionals? Really?