MUNICH - Audi says its high-performance RS4 Avant quattro is a combination of supercar and station wagon. Audi will build 3,000 units this year - and all are sold out. The RS4 quattro is powered by a special version of the 2.7-liter, 380hp, twin-turbocharged V-6 engine already in service in the Audi S4 Avant quattro. The uprated engine gives the RS4 a 0-100kph acceleration time of just 4.9 seconds. It was developed by quattro GmbH, the in-house tuner owned 100 percent by Audi, with help from Cosworth Technologies of the UK. The RS4 costs DM129,085 (A65,380) in Germany.