I have no info for the price of Audi ceramic brakes but i have heard about Porsche's ones:

For the first time PCCB Porsche Ceramic Composite Brakes are available as individual equipment on the new 911 Carrera and 911 Carrera S. The retail price in Germany incl VAT is Euro 7,830 and in the USA Dollar 8,150.

Measuring 350 millimetres or 13.78" in diameter, these cross-drilled, inner-vented composite ceramic brake discs weigh approximately 50 per cent less than metal discs and reduce unsprung masses on the Carrera S by 14 kilos or 34.4 lb. In conjunction with the brake pads also quite different in design and material, the ceramic brake discs immediately build up a high and, in particular, consistent level of friction during application.

Brake pad abrasion is kept to a minimum in comparison with metal brake discs thanks to the extremely hard surface of the ceramic discs. Life expectancy is correspondingly long, with the additional benefit that the material used cannot corrode. For ceramic brake discs are not affected in any way by salt grains or liquid salt on the road.

For the first time the new Carrera features ceramic brake discs enhanced to an even higher standard, the new design of the interior cooling ducts increasing the flow of cool air through the spinning disc. At the same time the larger number of cooling ducts increases disc rigidity, in the process significantly reducing deformation of the disc under high pressure. A further point is the optimisation of fibre reinforcement on the friction surface of the brake discs, significantly enhancing the resistance to abrasion particularly under high loads. For the customer, these improvements mean even better performance, enhanced brake comfort, and even longer brake system life.

Source: http://www.germancarfans.com/news.cf...porsche/1.html