The 911 has standard front 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 Viper doesn't offer side-impact airbags or side airbag protection for the head.
The 911 offers all wheel drive to maximize traction under poor conditions, especially in ice and snow. The Viper doesn’t offer all wheel drive.
Both the 911 and the Viper have standard driver and passenger frontal airbags, front seatbelt pretensioners, plastic fuel tanks, four-wheel antilock brakes, traction control and electronic stability systems to prevent skidding.
For smoother operation, better efficiency and fewer moving parts, the engines in the 911 have an overhead cam design, rather than the old pushrod design of the engine in the Viper.
The flat cylinder configuration of the boxer engine in the 911 lowers its center of gravity, enhancing handling stability. The Viper doesn’t offer a boxer engine configuration.
Regenerative brakes improve the 911’s fuel efficiency by converting inertia back into energy instead of wasting it. The Viper doesn’t offer a regenerative braking system.
In heavy traffic or at stoplights the 911’s engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. The engine is automatically restarted when the driver gets ready to move again. (Start/Stop isn’t accounted in present EPA fuel mileage tests.) The Viper doesn’t offer an automatic engine start/stop system.
The 911 RWD’s standard fuel tank has almost a gallon more fuel capacity than the Viper (16.9 vs. 16 gallons), for longer range between fill-ups. The 911 Carrera 4’s standard fuel tank has 2 gallons more fuel capacity than the Viper (18 vs. 16 gallons).
The 911 offers optional heat-treated ceramic brake rotors, which last ten to twenty times as long as conventional cast iron rotors, don’t rust, don’t fade during repeated high speed braking, and their lighter weight contribute to better braking, handling and acceleration. The Viper doesn’t offer ceramic brake rotors.
For better ride, handling and brake cooling the 911 has standard 19-inch wheels. Only 18-inch front wheels are available on the Viper. The 911 offers optional 20-inch wheels.
The 911 offers active sway bars, which help keep it flat and controlled during cornering, but disconnect at lower speeds to smooth the ride and offer greater off-road suspension articulation. This helps keep the tires glued to the road on-road and off. The Viper doesn’t offer an active sway bar system.
The 911 offers optional vehicle speed sensitive variable-assist power steering, for low-effort parking, better control at highway speeds and during hard cornering, and a better feel of the road. The Viper doesn’t offer variable-assist power steering.
For better maneuverability, the 911’s turning circle is 4.1 feet tighter than the Viper’s (36.4 feet vs. 40.5 feet).
The Porsche 911 may be more efficient, handle and accelerate better because it weighs about 50 to 250 pounds less than the SRT Viper.
The 911 has standard seating for 4 passengers; the Viper can only carry 2.
The 911 Coupe has 1.4 inches more front headroom and 3.1 inches more front legroom than the Viper Coupe.
When two different drivers share the 911, the optional memory system makes it convenient for both. Each setting activates different, customized memories for the driver’s seat position, steering wheel position, outside mirror angle, climate settings and radio stations. The Viper doesn’t offer a memory system.
The 911’s optional easy entry system raises the steering wheel and glides the driver’s seat back when the door is unlocked or the ignition is switched off, making it easier for the driver to get in and out. The Viper doesn’t offer an easy entry system.
If the windows are left down on the 911 the driver can raise them all using the key in the outside lock cylinder; on a hot day the driver can lower the windows. The driver of the Viper can only operate the windows from inside the vehicle, with the ignition on.
The 911’s rain-sensitive wipers adjust their speed and turn on and off automatically based on the amount of rainfall on the windshield. This allows the driver to concentrate on driving without constantly adjusting the wipers. The Viper’s manually variable intermittent wipers have to be constantly adjusted.
Heated windshield washer nozzles are standard on the 911 to prevent washer fluid and nozzles from freezing and help continue to keep the windshield clear in sub-freezing temperatures. The Viper doesn’t offer heated windshield washer nozzles.
To improve rear visibility by keeping the rear window clear, the 911 offers an optional rear wiper. The Viper doesn’t offer a rear wiper.
The 911’s sun-visors swivel front-to-side to block glare from the side windows. The Viper’s visors are fixed into the windshield header.
The 911’s standard outside mirrors include heating elements to clear off the mirrors for better visibility. The Viper doesn’t offer heated side mirrors.
When the 911 is put in reverse, the passenger rearview mirror tilts from its original position. This gives the driver a better view of the curb during parallel parking maneuvers. Shifting out of reverse puts the mirror into its original position. The Viper’s mirror doesn’t automatically adjust for backing.
The 911 offers optional automatic dimming rear and side view mirrors which automatically darken quickly when headlights shine on them, keeping following vehicles from blinding or distracting the driver. The Viper has an automatic rear view mirror, but its side mirrors don’t dim.
The 911 offers optional heated front seats, which keep the driver and front passenger extremely comfortable in the winter. Heated seats aren’t available in the Viper.
The 911’s optional air conditioned front seats cool the driver and front passenger and help take the sting out of hot leather in Summer. The Viper doesn’t offer air conditioned front seats.
The 911’s standard dual zone air conditioning allows the driver and front passenger to choose two completely different temperatures so people with different temperature preferences won’t have to compromise. This makes both the driver and front passenger as comfortable as possible. The Viper doesn’t offer dual zone air conditioning.