The supercharged S-Type R joined the lineup in 2003, and the hope was that it would compete with BMW's M5 and the Mercedes E55 AMG. The "R" was powered by a supercharged V8 producing 400hp (300kW; 410PS) and could accelerate from 0 to 60mph (97km/h) in 5.3 s (0 to 100km/h (62mph) in 5.6 s). It included 18 in (457 mm) alloy wheels, wire-mesh grille and dramatic monochromatic paint. The "R" also has a sportier rear apron, side-skirts, and front apron with built-in fog-lamps, a rear spoiler, a brace located near the rear subframe, and "R" badging on the boot lid and both front wings. It was the most expensive S-Type, with a base price of £50,040 in the UK
(US$58,995 in the United States).
Also added for 2003 model was an electronic parking-brake paddle-switch, which replaced the conventional manually-operated lever for the rear brakes.
A minor facelift in 2004 refined the S-Type's overall appearance, with the addition of redesigned standard front and rear aprons, slightly modified grille to include the Jaguar badge, remodeled rear light clusters, an aluminium bonnet, and a new 2.7 L V6 diesel engine. The windscreen washer jets were incorporated into the windscreen wiper arms. Internally, the center console was redesigned to incorporate the revised switch-gear and radio (or optional satellite navigation equipment).
From 2003, the rear-wheel-drive S-Type was produced with either a 5-speed manual transmission or a 6-speed J-Gate transmission that allows automatic gear selection or clutchless manual gear selection. The 2004 diesel sport saw the introduction of a 6-speed manual transmission. From model years 2000 to 2002, the S-Type was equipped with either a 5-speed manual or 5-speed J-Gate Ford 5R55N transmission.
The vehicle was powered by a variety of petrol and diesel engines. The 2.5 L V6 engine was not available for vehicles exported to the United States and Canada.
- 2.5 L V6 201hp (150kW; 204PS) 2003-2005
- 3.0 L V6 240hp (180kW; 240PS)
- 4.0 L V8 282hp (210kW; 286PS) 1999-2002
- 4.2 L V8 300hp (220kW; 300PS) 2003-2008
- 4.2 L V8 supercharged 400hp (300kW; 410PS) 2003-2008
- 2.7 L V6 Twin-turbo diesel 207bhp (154kW; 210PS) 2004-2008