The Focus RS Mk1 was produced from 2 October 2002 to 11 November 2003 and was Ford's return to the RS (Rallye Sport) badge after the demise of the tweaked Escorts, particularly the fabled Ford Escort RS Cosworth. Production was limited to 4501 units only. The car was largely built on its own assembly line in Ford's Saarlouis plant, with some additional specialist off-line assembly performed by the ACÜ group at Überhern. The RS was offered all over Europe, but 2147 were sold in the United Kingdom, by far its largest market. The Mark 1 Focus RS was a limited production run available in 21 European countries.

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More bespoke than the prior Ford Focus ST170, the Focus RS upgraded or replaced 70% of the standard Focus mechanicals. The turbocharged straight-4 engine produced a minimum of 215 PS and 310 Nm of torque, which was then mated to the 5-speed MTX-75 and not the Getrag transmission used in the ST170. Mechanically, most notably, the car incorporated a Quaife automatic torque biasing differential to improve traction from the front-wheel drive setup. The steering used a similar quick-ratio rack as the ST170 while the brakes used fixed-caliper, four-piston Brembo units with 324 mm discs at the front and single-piston floating calipers and 280 mm discs at the back. Wheels were 18" alloys specially developed by OZ Racing. The engine was heavily modified with forged aluminium pistons, hardened valve seats, sodium-filled exhaust valves, stainless steel exhaust system. The forced induction system comprised a Garrett turbocharger with a water-cooled charge air cooler and an electric water pump. To transmit the higher torque an upgraded AP clutch was used.

 

The Focus RS was available in one metallic colour, Imperial Blue. The body looked similar to the standard Focus or to the ST170, although the RS featured unique front and rear bumper assemblies required for the wider wheel arches which accommodated the 65 mm wider front track. Internally, the theme is blue and black with sections of blue leather trim on the door trim panels, the steering wheel and the Sparco seats which were trimmed in blue/black leather and Alcantara. A green starter button starts the engine. The instruments have a blue background and in place of the coolant temperature gauge, the RS was equipped with a boost pressure indicator (up to 1.5 bar). The gear lever knob, handbrake lever, and pedals were all custom made by Sparco.

 

All-around performance was roughly equal or better to its other competitors, including hatchbacks such as the Honda Civic Type-R and some four-wheel drive cars in the same price field. Power was a diminished priority and the handling on a track, courtesy of the front differential, was considered by most observers to be its strongest characteristic.