Is Audi's new model the best estate car in the world?

That’s right. The estate version of Audi’s sublime executive A6 range is a motor in demand. It is good at shifting loads, but it is even better at turning heads.

Now the fourth generation model is on its way. It will be available to order from November with deliveries starting in January.

And while such a powerful beast with power to burn can’t claim to be environmentally friendly, this new model does have some green credentials.

It is a 4.0 litre twin-turbo mild hybrid with cylinder-on-demand technology, helping to deliver epic performance as responsibly as possible.

With the exception of the front doors, roof and tailgate, the exterior of the RS 6 Avant comprises exclusively RS-specific parts, and to look at the car at rest on its sizeable 21-inch wheels shrouded by broad flared arches that expand its width considerably, this is immediately evident.

The new RS 6 Avant is one of the first Audi Sport models to feature the new RS design language. In addition to a new bonnet with powerdome, it also adopts the front headlights from the A7 model line which are not only slimmer and more sporting in style but also offer the RS Matrix LED laser headlights.

The powerplant is key. The 4.0 TFSI in the new Audi RS 6 Avant delivers 600PS. It touches 60mph in 3.6 seconds. Top speed is electronically governed at 155mph.

Thanks to the 48-volt main electrical system the twin-turbo V8 combines maximum performance with high efficiency. A belt alternator starter lies at the heart of the mild hybrid system (MHEV). Up to 12 kW of power can be recovered during light deceleration and stored in a separate lithium-ion battery. If the driver lifts off the accelerator at a speed of between 34 and 99mph, the Avant recovers energy or coasts for up to 40 seconds with the engine switched off.

For all its efficiency the 4.0 TFSI remains a thoroughbred V8 in terms of character and sound.