For rear fog lamps you’ll need 21 W power bulbs and base type BA15S SCC. Lots of vehicles including Audi R8 possess rear fog lamps. You should always check if in your Audi R8 5.2 back antifogs work well. Standard volt feature of 12 V lamps is installed in R8. In every car with motor volume 4.2 there were used good Audi bulbs. For all 2011 cars which have engine code CTYA it supports safety during fog.
With any troubles of fog lamps in 2009 Audi R8 go to service depot. Nevertheless, you might choose different BA15S SCC type lamp to suit 5.2 car with motor number CMPA. Among all 12 V car lights choose those which have 21 W power. Rear fog lamp made by Audi which is original will be good choice for R8 4.2.