Visually, the RS 6 differed from the related S6, having flared front and rear wheel arches (fenders), harking back to the original Audi Quattro, to allow for a wider wheel track. It also had no front fog lights to allow for larger frontal air intakes (for the two side-mounted intercoolers (SMICs), and additional radiators). The ten (per side) front light-emitting diode (LED) daytime running lights (DRLs) are located within the main headlamp housing on the RS 6 in order to increase the size of the air intakes, whereas similar LEDs (but five per side) on the related S6 are found adjacent to the fog lamps in the lower front bumper. LED lighting technology was also used in the rear lights. The RS 6 also included adaptive headlights, which swivel around corners in conjunction with steering wheel movements. The facelifted Audi A6, released as a 2009 model, received similar front and rear-end LED lighting styling to that pioneered on the RS 6.