Audi success has been built on the sum of its parts, writes Robin Roberts. Whether that’s quattro technology, TT-style or out-and-out performance through the wheels of the R8, but it’s also been piling up sales with estates. The runaway demand for its RS4 and RS6 estate or avant models over years is probably better known than the popularity of its 100 and then A6 wagons, and the A6 last year … [Read more...]