This thing is called Darrian GTR and was originally built as an Endurance GT racer , but later transformed into a Tarmac Rally Car. It is powered by one of the first Cosworth derived Millington Diamond engines. It became the Darrian Works supported car with continuous developments after to suspension, gearbox and every development of the Millington engine. In this guise it had beaten full WRC cars in stage rallys, a fearsome piece of kit. The engine is a 347bhp Millington diamond series 2 with Hewland transaxle, paddle shift traction and launch control. That 347bhp and 250lbft of torque is more than enough to propel the sub 900kg car along at serious speed.
Here you can see it at Retro Rides Gatherng 2017 where it was one of the Guest cars, and unfortunately some reliablity issues prevented it from displaying a more impressive Demonstration ru, but still it is a incredibly rare machine that deserves to be shown to a larger public.