Just about every brand that offers some flavor of all-wheel-drive has slapped a proprietary name on its system. For BMW it's xDrive, SH-AWD for Acura, 4Motion for Volkswagen and so on. However, none has developed anywhere near the cachet of Audi's iconic Quattro. Audi was among the first to show that four driven wheels could increase performance in any conditions, and now, more than 40 years since the Quattro technology came sliding sideways into the world, it's being completely upended.

Quattro as a label has been applied to many different differential configurations and technologies over the years, but with the release of the all-electric E-Tron line, it's being reinvented like never before. Audi's 591-horsepower, $143,895 RS E-Tron GT is the top of the pile for this electrified generation of Quattro. As for the more traditional, gear-driven Quattro, you'd be hard-pressed to do better than the RS6 Avant, a 591-horsepower, $117,595 super-wagon. Driving the two back to back on a snowy, icy, rally super-special stage? It's the stuff of dreams -- and also a perfect chance to compare old and new.

Traditional forms of all-wheel drive rely on three differentials, effectively sets of gears that take power from one source and split it in two. The center differential takes the engine's power and sends it to both the front and rear axles. Then, differentials at either end send the power out to each of the four wheels.