So which one is faster? MotorTrend states it is the E63 AMG S once again struggling to interpret what trap speed means. The E63 AMG is QUICKER, not faster. It runs through the 1/4 mile at firstname.lastname@example.org compared to the M5's email@example.com. This network called MotorTrend a bunch of morons last week for not understanding how trap speed relates to performance and this network will do so once again this week.
Yes, the E63 is quicker as to be expected with its all wheel drive. The M5 is faster due to its higher trap speed. What does this mean? Simply that the E63 will cross the 1/4 mile marker quicker than the M5 but the M5 is pulling harder at the 1/4 mile marker. Essentially, from a roll the M5 is favored in a race and from a stop the E63 is favored in a race by virtue of its traction advantage. Both cars are incredibly close to one another but why MotorTrend struggles with digesting basic information is anyone's guess.
Does the 4Matic on the AMG comes with a weight penalty? Yes. It's up to a hefty 4511 pounds. The M5 is no lightweight but it is lighter at 4369 pounds. The difference is not huge but it has been a while since one could say an M model was decisively lighter than the competition.
MotorTrend takes both cars to the dyno at K&N but unfortunately the dyno they have is a SuperFlow dyno. Why does this matter? Because versus the more popular Dynojet the SuperFlow dyno tends to read higher by about 10-12%. Keep that in mind when looking at the peak output figures. The E63 hits 541 to all four wheels whereas the M5 manages 508 to the wheels. What we can take away from this is the AMG is putting out more power but the all wheel drive drivetrain and extra weight due to it sap some of the performance making things fairly equal despite the raw power advantage. The automatic transmission in the E63 also will not be as efficient as the dual clutch transmission in the M5.
Enough about power and acceleration, what about the driving experience and handling? The M5 steering is stated to be heavy but slightly numb which is a common complaint with new M's. MotorTrend does state the M5 Competition Package is superior to the M5 and addresses many complaints. It still is slightly isolated though, not what one expects in their M.
MotorTrend states the heavier E63 AMG feels lighter oddly enough. The AMG's steering and feedback seems to be preferred. The reviewers seem to be split on the aspect as to which one is more fun in the canyons as the AMG's transmission is stated to be a liability in canyon carving as far as response is concerned. If you could combine the M5's transmission with the E63's steering feel you might have the world's perfect luxury performance sedan.
Honestly, these are both amazing sedans. AMG has really stepped up their game and BMW has essentially "fixed" what was wrong with the M5. You can't go wrong either way.