For enhanced safety, the front and rear seat shoulder belts of the Mercedes AMG E-Class Cabriolet have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision and force limiters to limit the pressure the belts will exert on the passengers. The Porsche 911 doesn’t offer pretensioners for its rear seat belts.
The AMG E-Class Cabriolet’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The 911 doesn’t offer pre-crash pretensioners.
The Mercedes AMG E-Class Cabriolet has a standard driver’s side knee airbag mounted low on the dashboard. The knee airbag helps prevent the driver from sliding under the seatbelts or the main frontal airbag; this keeps the driver better positioned during a collision for maximum protection. A knee airbag also helps keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The 911 doesn’t offer knee airbags.
The AMG E-Class Cabriolet has standard front and rear seat side-impact airbags and head airbags, which act as a forgiving barrier between the passengers and the door. Combined with high-strength steel door beams this system increases protection from broadside collisions. The 911 doesn't offer rear-seat side-impact airbags, only ones for front seat occupants.
Over 200 people are killed each year when backed over by motor vehicles. The AMG E-Class Cabriolet has a standard Maneuvering Brake Function that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The 911 doesn’t offer backup collision prevention brakes.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the AMG E-Class Cabriolet. But it costs extra on the 911.
The AMG E-Class Cabriolet has a standard blind spot warning system that uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them and moves the vehicle back into its lane. A system to reveal vehicles in the 911’s blind spot costs extra.
To help make backing out of a parking space safer, the AMG E-Class Cabriolet has standard Rear Cross-Traffic Alert and Active Brake Assist automatically engages the brakes to help avoid a collision. Porsche charges extra for rear cross-path warning on the 911.
The AMG E-Class Cabriolet’s driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The 911 doesn’t offer a driver alert monitor.
Both the AMG E-Class Cabriolet and the 911 have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights, rearview cameras and available lane departure warning systems.
The Mercedes AMG E-Class Cabriolet weighs 818 to 1482 pounds more than the Porsche 911. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.