Watch this Audi S1 Group B racer tear up the Kyustendil Hillclimb

Bulgarian tuner Prospeed has built a replica of Audi's fabled S1 World Rally Championship mauler out of a garden-variety Audi Coupe, and it's a convincing-looking beast. Helping in its bid for authenticity is genuine Group B horsepower: 800 ponies, to be exact. It won the Bulgarian Hillclimb Championship last year, and it recently ran up an incline at the Kyustendil Hillclimb, part of this year's championship series.

The list of modifications made to the donor car are intense, and so is the sound of the final product, singing like a crazed goldfinch as driver Nikolay Zlatkov races to the top of the hill. You can have a watch and a listen in the video below.