Back in the 1980s the Ford Sierra Cosworth was known as something of an ordinary man's supercar as it cost much less than most cars offering the kind of stunning performance it could deliver. But if you want to get your hands on an original example from 1987 that's soon going under the hammer at the Silverstone Classic Sale in the U.K., it's not going to be quite as affordable.

The model in question is a 1987 Sierra RS500 Cosworth which is number 38 of the only 500 units of the mighty Ford that were ever built. It's going up for sale for the first time since 1988, and it's only done 10,840 miles since it left the factory. As well as being used so little during its lifetime, the Ford homologation model also boasts a well-documented history that includes service receipts, previous MOTs and SORN notices.

When the Sierra was originally launched back in 1982, despite its unique styling it didn't really strike a chord with the car-buying public right away. To help shine a light on the standard car and boost disappointing early sales, Ford turned to motorsport to enhance the image of the Sierra.

To meet motorsport homologation rules so the Sierra would be eligible for Group A International Touring Car competition, Ford needed to build 5,000 Sierra Cosworth units and 500 road-going derivatives of the hardcore RS500. To do this, the manufacturer enlisted the help of Aston Martin to convert the 500 right-hand drive models and boost their power to 224 bhp, although that could then be increased to a much more impressive 400 bhp with the cars in full race specification. The car also benefited from a number of aerodynamic enhancements along with larger cooling ducts for the brakes and engine intercooler.

It was originally intended that all 500 units of the RS500 would be finished in black, but in the end 52 were produced in blue and 56 in white. The car going under the hammer at the Silverstone Classic Sale to be held on July 21 to 22 is one of the more common black variety, but it still won't come cheap as it has an estimate on it of £105,000 ($139,556/€119,816).