If the current XKR-S coupe and convertible models are anything to go on, the four-door XFR-S should be powered by a more potent version of Jaguar's 5.0-liter supercharged V8, producing around 550 horsepower. Expect some suspension enhancements to be on board, as well, along with some exhaust tuning to make the big cat growl louder than ever before.
When it launches, the XFR-S will battle head-to-head with the likes of the 560-hp BMW M5 and 518-hp Mercedes-Benz E63 AMG (or 550 with the optional AMG performance pack). For reference, the standard XFR produces 510 hp from its detuned version of the supercharged V8.
We expect more details to arrive closer to the car's alleged November debut. For now, click through the attached high-res gallery to see spy shots of the XFR-S testing at the Nürburgring.