Audi unleashes lighter versions of RS 4 and RS 5

Audi had announced it will offer lighter 'Carbon Edition' versions of both its recently revealed RS 4 Avant wagon and the current RS 5 coupe.

The weight savings come from widespread use of carbon-fibre-reinforced (CFRP) components which Audi claims flow directly from its motorsport programs.

Audi's fast RS 5 coupe sheds an impressive 80kg thanks to an exposed CFRP roof, rear spoiler, diffuser and sill extensions, plus door mirror caps.

Combined with all-new, larger 20-inch alloy wheels [saving as much as 2kg each compared to the normal 19-inch rims] the total weight for the coupe drops to 1585kg.

The RS 4, meanwhile, misses out on the CFRP roof and spoiler, but gets all the other weight saving bits and pares 60kg, dropping its total kerbweight down to 1730kg.

Inside, both score plenty of CFRP interior inlays and the Audi RS super-sport seats.

Despite the lightweight theme, there's no skimping on technology, with both cars including as standard the 8.0-inch infotainment system and the fully digital 12.3-inch virtual cockpit instrumentation.

Other standard kit includes carbon ceramic brakes, the quattro sports limited slip differential and Dynamic Ride Control.

Despite the considerable weight-savings, Audi makes no claims for improvements in performance figures.

Both cars are powered by the 331kW/600Nm twin-turbo 2.9-litre V6 and the RS 4 accelerates to 100km/h in 4.1 seconds while the coupe is a few tenths quicker at 3.9 seconds.

Top speed remains pegged at 280km/h with the RS Dynamic Package fitted.

Audi says, despite being a special edition, the 'Carbon Edition' models will not be volume limited.

While not yet confirmed for Australia, in the UK the RS 4 Avant carries a £10,000 ($A17,000) premium over the standard wagon while the fast coupe commands a punchier £12,500 ($A21,000) price penalty over the regular coupe.

The RS 4 and RS 5 Carbon Editions go on sale in Europe in March 2018.