The X6 M has standard Active Head Restraints, which use a specially designed headrest to protect the driver and front passenger from whiplash. During a rear-end collision, the Active Head Restraints system moves the headrests forward to prevent neck and spine injuries. The ML63 doesn’t offer a whiplash protection system.
When descending a steep, off-road slope, the X6 M’s standard Hill Descent Control allows you to creep down safely. The ML63 doesn’t offer Hill Descent Control.
Both the X6 M and the ML63 have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, front seatbelt pretensioners, plastic fuel tanks, four-wheel antilock brakes, all-wheel drive, traction control and electronic stability systems to prevent skidding.
The X6 M’s corrosion warranty is 8 years and unlimited miles longer than the ML63’s (12/unlimited vs. 4/50,000).
BMW pays for scheduled maintenance on the X6 M for 4 years and 50,000 miles. BMW will pay for oil changes, lubrication and any other required maintenance. Mercedes doesn’t pay scheduled maintenance for the ML63.
There are over 12 percent more BMW dealers than there are Mercedes dealers, which makes it easier should you ever need service under the X6 M’s warranty.
J.D. Power and Associates’ 2014 Initial Quality Study of new car owners surveyed provide the statistics that show that BMW vehicles are better in initial quality than Mercedes vehicles. J.D. Power ranks BMW 8th in initial quality, above the industry average. With 7 more problems per 100 vehicles, Mercedes is ranked 13th.
The X6 M’s 4.4 turbo V8 produces 49 more horsepower (567 vs. 518) and 37 lbs.-ft. more torque (553 vs. 516) than the ML63’s standard 5.5 turbo V8. The X6 M’s 4.4 turbo V8 produces 17 more horsepower (567 vs. 550) than the ML63’s optional 5.5 turbo V8.
On the EPA test cycle the X6 M gets better fuel mileage than the ML63 (14 city/19 hwy vs. 13 city/17 hwy).
Regenerative brakes improve the X6 M’s fuel efficiency by converting inertia back into energy instead of wasting it. The ML63 doesn’t offer a regenerative braking system.
For better traction, the X6 M has larger tires than the ML63 (F:285/40R21 & R:325/30R21 vs. 265/45R20).
The X6 M’s 285/40R21 front and 325/30R21 rear tires provide better handling because they have a lower 40 series front and 30 series rear profile (height to width ratio) that provides a stiffer sidewall than the ML63’s standard 45 series tires. The X6 M’s tires are lower profile than the ML63’s optional 35 series tires.
For better ride, handling and brake cooling the X6 M has standard 21-inch wheels. Smaller 20-inch wheels are standard on the ML63.
The X6 M offers an available adjustable active suspension system, which counteracts cornering forces actively, limiting body roll and improving handling and stability. Mercedes doesn’t offer an active suspension on the ML63.
The X6 M’s front to rear weight distribution is more even (51.6% to 48.4%) than the ML63’s (54.9% to 45.1%). This gives the X6 M more stable handling and braking.
The X6 M has 1 inch more front headroom, 3 inches more front shoulder room and 1.2 inches more rear shoulder room than the ML63.
Unlike the driver-only memory system in the ML63, the X6 M has standard driver and passenger memory, so that when drivers switch, the memory setting adjusts the driver’s seat, steering wheel position, outside mirror angle, climate settings and radio stations and the front passenger seat also adjusts to the new passenger’s preset preferences.
The X6 M offers an optional heads-up display which projects speed and navigation instruction readouts onto the windshield, allowing drivers to view information without diverting their eyes from the road. The ML63 doesn’t offer a heads-up display.
Heated windshield washer nozzles are standard on the X6 M to prevent washer fluid and nozzles from freezing and help continue to keep the windshield clear in sub-freezing temperatures. The ML63 doesn’t offer heated windshield washer nozzles.
To improve rear visibility by keeping the rear window clear, the X6 M has a standard rear variable intermittent wiper with a full on position. The rear wiper standard on the ML63 only has an intermittent setting, so in a hard rain visibility isn’t as good.