Highlights Twin-turbo 5.0-litre V10 super-estate Dyno-proven MRC Stage 2 performance with 716bhp Quality named-brand modifications throughout, all documented Presents in very good, well-detailed condition throughout Comprehensive documented service history with a full A4 folder of invoices Overview Every so often a manufacturer builds something gloriously unreasonable, and the C6 Audi RS6 is exactly that.

It arrived with a twin-turbocharged 5.0-litre V10, 580bhp in standard tune and the pace to reach 62mph in 4.6 seconds while still swallowing 1,660 litres of luggage.

It remains the only 10-cylinder RS6 Audi has built, quattro all-wheel drive putting the lot down without drama up to a limited 155mph.

This particular Avant, finished in metallic grey, takes that already generous recipe several steps further.

It's a properly sorted, dyno-proven MRC Stage 2 car, its printout recording a hefty 726 PS and 1,067 Nm, backed by a considered list of quality named-brand modifications that are...