More significant still, however, is an Audi all-wheel-drive system whose centre differential normally pushes 60 percent (but can divert as much as 85 percent) of the RS5's torque to the rear axle; there, an electronically controlled differential does the job of a mechanical limited-slip diff.
Coupled to this is torque vectoring for all four wheels; it can apply the brakes to individual wheels, in effect diverting power to other wheels.
One last, slightly more controversial addition to this array of hardware and software makes its way onto our test car: Dynamic Steering, an active steering option that alters the steering ratio dependent on speed; it's quicker at low speeds, ostensibly for easier manoeuvring.
Along with the plethora of adjustable drivetrain features, the RS5 also allows its driver to tailor the dynamic experience. The RS5 has electromagnetically controlled dampers that can be set to Comfort, Auto or Dynamic modes that give its driver the opportunity to adjust the steering, engine response and sport differential over a similar range.
The first reassuring thing about the RS5 is that, unless you're determined to make it otherwise by selecting inappropriate damper settings, it rides pleasingly deftly.
But, boy, the RS5 is able if you’re pressing on; it's a properly quick point-to-point mover. Body movements remain tight, grip and traction are as high as you'd expect and, in extremis, you can feel the various machinations beneath the body apportioning power to where it most needs to go.
All the chassis sophistication in the world, however, can't disguise the 12 percent extra weight the Audi carries in comparison with its BMW foe. During this test we drove the two back to back across one of the world's most demanding test roads. The RS5 eked out a small speed advantage over the M3, but only by retaining better traction in slower corners.
But when it came to going, stopping and grip, the more agile M3 had the edge. More crucially, though, the BMW was also the more entertaining car to drive.