adjust the stiffness at each damper constantly to maintain both a comfortable ride and a high grip. In this version, it has a three-way level control, selectable from the Multi Media Interface controls. The steering system includes rack and pinion speed-dependent "servotronic" power steering, with a ratio of 12.5, and a turning circle of 12.2 metres. C6 brakes, wheels and tires The standard brakes on the RS 6 are cross-drilled, radially vented, and floating iron discs. At the front they are diameter and thick, clamped by gloss black six-piston fixed Brembo monoblock alloy calipers incorporating the "RS" logo, and at the rear they are diameter and with black single-piston floating calipers and an integrated electro-mechanical parking brake linkage. The parking brake serves doubles as a full emergency brake whilst the car is in motion, by applying maximum braking effort to all four wheels, resulting in activating the Anti-lock Braking System (ABS). Optional "Audi ceramic" Carbon fibre-reinforced Silicon Carbide (C/SiC) composite front brakes are available, only with 20-inch wheels, which use diameter by thick drilled, vented, and floating SGL Carbon composite discs, with grey painted eight-piston fixed Alcon monobloc alloy calipers with the "Audi ceramic" logo. Irrespective of the type of disc construction, all brake discs are mounted via high strength steel mounting pins which connect the 'working' surface of the disc to lightweight alloy disc hubs. A specifically 'tuned' "sport-biased" Bosch ESP 8.0 Electronic Stability Programme is standard, and includes Anti-lock Braking System (ABS) and Electronic Brakeforce Distribution (EBD), and Brake Assist (BA). This ESP system has three user-selectable settings: "ESP-on" - the standard default full protection mode, "ESP-sportmode" (which turns off the ASR and EDL traction functions), and "ESP-off" (which fully disables all 'stability' and 'traction' related functions). Standard wheels (in the UK) are 9.5Jx20-inch '5-segment-spoke' design alloy wheels running on (eXtra Load) tyres (rated at per tyre), with official supplies being either Pirelli P-Zero Rosso or Dunlop SP SportMaxx GT. No-cost options are 9.5Jx20 '7-arm double spoke' design (identical style to B7 RS 4), or 9Jx19-inch '10-spoke' design alloys with Michelin Pilot Sport PS2 tyres. C6 other notable features Digital Audio Broadcasting (DAB) digital radio tuner with DVD-based satellite navigation and Multi Media Interface (MMI), with optional hybrid digital/analogue TV tuner. Solar sunroof operating the air-con whilst the vehicle is stationary and the engine is turned off Rear window and rear side window manual sun blinds C7 (Typ