What is it?
So this is the new RS6 Avant, and the recipe remains pretty much the same as before. A big-engined version of the A6 Avant, all-wheel drive, auto 'box. But the execution is different. Cleverer. A 4.0-litre V8 instead of a 5.0-litre V10. Better balance. More thoughtful deployment of resources. Now, the previous bi-turbo V10 was an excellent express train for mauling Das Autobahn, but tended towards the bloodless when attempting a corner (it required extreme conditions to really show you what it was capable of), and fuelling it was like tipping buckets of unleaded down a car-shaped storm drain. So this version attempts to deal with some of those issues.
The RS6 now handles properly. The engine is short - only 497mm - compared with the old V10, and some clever positioning of bits means that the RS6 now has a much-improved balance front to rear. And it shows. It still leads slightly with the nose, but throw in the active diffs and general trickery, and this is a big estate that's proper fun - it'll even slide a bit, though you need space and a smaller imagination than I possess to do it much on a public road.
On the inside
Built from granite made to look like plastic. This is an interior other manufacturers should worship. Massively practical because it is just so massive. Use this car everyday and love it. Kill the Labrador accidentally with strenuous acceleration, make the kids go blue with fright; it’s all good.
Of course, adding lightness is good for efficiency, and the new RS6 is a decent chunk more fuel-efficient than the old version - up to 30 per cent. Part of that is down to clever aircon and thermal management, but there's also COD (Cylinder On Demand) tech in the engine, which we've seen before on various cars. This simply shuts down half the cylinders when running a light throttle. In the case of the RS6, if you're using under 3,500rpm on a constant load, then the car drops cylinders 2, 3, 5 and 8 out of service. Doing so generally reduces fuel consumption by about five per cent on the usual combined cycle, or as much as 12 per cent at a steady 62mph cruise. Which isn't to be sniffed at, especially as a twin-turbo V8 isn't likely to be particularly drink-shy if you decide to boot it.