For enhanced safety, the front and rear seat shoulder belts of the Audi S4 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 Volkswagen GTI doesn’t offer pretensioners for the rear seat belts.
The S4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The GTI doesn’t offer pre-crash pretensioners.
Both the S4 and GTI 4dr have child safety locks to prevent children from opening the rear doors. The S4 has power child safety locks, allowing the driver to activate and deactivate them from the driver's seat and to know when they're engaged. The GTI’s child locks have to be individually engaged at each rear door with a manual switch. The driver can’t know the status of the locks without opening the doors and checking them.
The Audi S4 has standard driver and front passenger side knee airbags mounted low on the dashboard. These airbags helps prevent the driver and front passenger from sliding under their seatbelts or the main frontal airbags; this keeps them better positioned during a collision for maximum protection. Knee airbags also help keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The GTI doesn’t offer knee airbags.
The S4’s standard pretensioning seatbelts also sense rear collisions and remove slack from the seatbelts to help protect the occupants from whiplash and other injuries. The GTI doesn’t offer a whiplash protection system.
The S4 has all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The GTI doesn’t offer all-wheel drive.
The S4 Premium Plus/Prestige has a standard Top View Cameras to allow the driver to see objects all around the vehicle on a screen. The GTI only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.
Both the S4 and the GTI 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, crash mitigating brakes, post-collision automatic braking systems, daytime running lights, rearview cameras, available blind spot warning systems and rear cross-path warning.
The Audi S4 weighs 637 to 714 pounds more than the Volkswagen GTI. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.
Instrumented handling tests conducted by the National Highway Traffic Safety Administration and analysis of its dimensions indicate that the S4, with its five-star roll-over rating, is 3.5% less likely to roll over than the GTI, which received a four-star rating.