For enhanced safety, the front and rear seat shoulder belts of the Jaguar XJ 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 Audi S8 doesn’t offer pretensioners for the rear seat belts.
Both the XJ and the S8 have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, height adjustable front shoulder belts, plastic fuel tanks, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights, blind spot warning systems, rearview cameras and available collision warning systems.
J.D. Power and Associates’ 2014 Initial Quality Study of new car owners surveyed provide the statistics that show that Jaguar vehicles are better in initial quality than Audi vehicles. J.D. Power ranks Jaguar second in initial quality, above the industry average. With 24 more problems per 100 vehicles, Audi is ranked 11th.
The XJR’s standard 5.0 supercharged V8 produces 30 more horsepower (550 vs. 520) and 21 lbs.-ft. more torque (502 vs. 481) than the S8’s 4.0 turbo V8.
In heavy traffic or at stoplights the XJ’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 S8 doesn’t offer an automatic engine start/stop system.
For better traction and acceleration, the XJ has larger standard rear tires than the S8 (275/40R19 vs. 265/35R21). The XJR’s rear tires are larger than the largest rear tires available on the S8 (295/30R20 vs. 275/35R21).
The XJR’s 295/30R20 rear tires provide better handling because they have a lower 30 series profile (height to width ratio) that provides a stiffer sidewall than the S8’s 35 series tires.
For a smoother ride and more stable handling, the XJ’s wheelbase is 1.6 inches longer than on the S8 (119.4 inches vs. 117.8 inches). The XJL’s wheelbase is 6.5 inches longer than on the S8 (124.3 inches vs. 117.8 inches).
For better maneuverability, the XJ’s turning circle is 1.4 feet tighter than the S8’s (39 feet vs. 40.4 feet).
The Jaguar XJ may be more efficient, handle and accelerate better because it weighs about 550 to 850 pounds less than the Audi S8.
Because it has more passenger and cargo room, the XJ is rated a Large car by the EPA, while the S8 is rated a Mid-size.
The XJ has .1 cubic feet more passenger volume than the S8 (102 vs. 101.9).
The XJ has 2.3 inches more front headroom, .1 inches more front legroom and .3 inches more rear legroom than the S8.
For enhanced passenger comfort on long trips the XJ L’s available rear seats recline. The S8’s rear seats don’t recline.
The XJ has a much larger trunk than the S8 (15.2 vs. 13.2 cubic feet).
If the windows are left down on the XJ the driver can raise them all using the key in the outside lock cylinder. On a hot day the driver can lower the windows from outside the vehicle using the key in the outside lock cylinder or the keyless remote. The driver of the S8 can’t use the remote to operate the windows.
When the XJ is put in reverse, both rearview mirrors tilt from their original position. This gives the driver a better view of the curb during parallel parking maneuvers. Shifting out of reverse puts the mirrors into their original positions. The S8’s mirrors don’t automatically adjust for backing.
Optional air conditioned front and rear seats keep the XJ’s passengers comfortable and take the sting out of hot leather in Summer. The S8 doesn’t offer air conditioned seats in the rear.
The XJ has a standard heated steering wheel to take the chill out of steering on extremely cold Winter days before the car heater warms up. A heated steering wheel costs extra on the S8.
The XJ was chosen as one of Automobile Magazine’s “All Stars” in 2011. The A8 hasn’t been picked since 2005.