The XJR is powered by the supercharged version of the 4.0 L V8. It is also equipped with sport suspension, wider wheels and tyres, and matte-black exterior window trim (except in the US market, where the XJR was given chrome window frames and rain gutters.) Like the Sport model, the XJR has a body-coloured radiator grille surround, but with a stainless-steel mesh insert rather than the normal vanes. Other exterior touches include the "XJR" rear badging and larger exhaust outlets.[12]

Available on late XJR models was an "R1" performance option. This included 18" BBS wheels, larger Brembo brakes with cross-drilled rotors, and re-tuned suspension.

The XJR was capable of reaching 97 km/h (60 mph) from a standstill in 5.6 seconds, with an electronically limited top speed of 249 km/h (155 mph).