Both the RS4 and R8 have a thumping 420hp and AWD chassis but one’s a fully fledged mid-engined sports car and the other is a family sedan on steroids, so as you’d expect both perform very differently. Only about 0.2 seconds separates the two cars in the sprint to 60mph but as the reviewer reveals in this latest video speed isn’t the primary deciding factor when it comes to the track.