Following are the main design features of the suspension dampening component classified as an Audi strut (not an Audi shock absorber). An Audi strut (a.k.a. MacPherson strut) contains a shock absorber and has been designed to perform multiple suspension functions.
On Audi models a struts primary function is to act as a shock absorber, dampening the impacts of road irregularities. Audi struts also carry the coil spring on which the vehicles body is supported. The upper portion of an Audi strut usually has a built in steering arm that a steering tie rod attaches to. The strut assembly also pivots, controlling the steering of the wheels. The design of an Audi strut eliminates the need for an upper control arm. However, it always needs to be supported with a lower control arm. Another unique design feature of some Audi struts (depending on model) is a replacable internal shock absorber cartridge. This cartridge is mounted inside the strut and can be replaced when it is worn out.
The strut assembly plays a major part in supporting the vehicle and is a major member of the suspension system. On the other hand an Audi shock absorber doesn't do any of the above with one exception. On rear Audi suspension systems the shock absorber is used in conjunction with a coil spring to support the rear of the vehicle. Otherwise the primary function of the shock absorber is just for dampening.
From 1978-1995 all Audi models front suspensions were equipped using a strut assembly design. Starting in 1996 with the introduction of the A4 and 1998 with the Vw Passat, they began using a very complex 8 piece control arm front suspension design utilizing just a shock absorber for dampening. This complex 8 piece control arm and shock absorber design is still being used on the larger platform Audi A4, A6, A8 models. Vw discontinued the 8 piece control arm design around 2006. With the exception of the Phaeton and Toureg models which still use shock absorbers all other Vw models, Jetta, Golf, Rabbit, EOS and Beetle utilize strut assemblies. The popular Audi A3 models uses a strut system.