The 2021 Audi RS Q8 is one of a burgeoning number of super-SUVs that offer astonishing performance at an astonishing price.At $208,500 plus on-road costs, the RS Q8 is actually among the cheapest of them.There’s the $218,900 BMW X6 M Competition that is an obvious competitor and the new $225,500 Mercedes-AMG GLE 63 S Coupe that is just entering showrooms.There’s also a slew of Porsche Cayenne models priced either side of the RS Q8, various Maserati Levante variants and more than one Range Rover to choose from.Developed by Audi Sport, which is Audi’s AMG equivalent, the RS Q8 is the company’s most extreme SUV yet. It takes the standard Q8 five-door, five-seat ‘coupe’ SUV and dials the wick up very high.