Most of the chassis for the 1986 Jaguar XJ6 was basically Series III, albeit with new components and some notable changes. The rear disc brakes, for instance, sat outboard instead of inboard, and actuation was hydraulic instead of vacuum to accommodate Bosch anti-lock electronics.
Unique to Jaguar's ABS was "yaw control," which compensated for side-to-side variances in surface friction. The lower rear wishbones' inner pivot points were situated to provide a so-called pendulum action claimed to limit toe and camber changes while providing higher lateral stiffness for hard cornering; a reworked front subframe eliminated camber adjustments. Also new was hydraulic rear leveling via an engine-driven pump shared with the brakes (which got electronically mandated priority in the event of a fluid leak or other malfunction).
Other features new to Jaguar gave the latest XJ6 more of what the British call "showroom appeal." Base and pricier Vanden Plas models returned with standard eight-way power front seats, a 13-function Vehicle Condition Monitor (VCM), vacuum-fluorescent bar-graph engine gauges (analog speedometer and tachometer were retained and were also electronic), and heated door locks, door mirrors, and windshield-washer nozzles. The VP adds headlight washers (also heated) and front seat heater, plus limited-slip differential, rear reading lights, and drop-down wood picnic tables on the rear of the front seatbacks.
Standard for both models were a revised automatic climate system and trip computer (the latter sharing its display with the VCM), electric sliding sunroof, telescoping steering wheel (which now carries the column stalks with it), and the obligatory super-sophisticated sound system. As before, there were no options for U.S. models apart from colors.
Incidentally, the American XJ6 was something of a hybrid. It was basically the upmarket European Sovereign -- now a Jaguar, not a Daimler -- with the base model's four round headlamps instead of dual flush-mount types. Jaguar also offers a somewhat less lavish "economy" XJ6 powered by a 2.9-liter single-cam engine with Bosch injection, rated at 165 horsepower.
As mentioned, the new XJ6 had been well received. One British magazine was quick to name it "the world's best sedan," though that kind of nationalistic flag-waving is, perhaps, to be expected. Nevertheless, the consensus in both Europe and America seemed to be that XJ40 was even quieter than the popular Series III; rode just as well, if not better; possessed as much flexibility and grace; and had even better steering and handling. Both the U.S. and European versions had proven faster than the old XJ6 4.2, and could be significantly more economical when driven with restraint. The most controversial aspect, perhaps, was the mixing of an analog speedometer and tachometer with vacuum-fluorescent bar-graph engine gauges. Full-analog instrumentation had been rumored.
Of course, one can always find flaws in any car no matter how carefully planned, but Jaguar thought it had a Mercedes/BMW-beater in its XJ6.
Meantime, the new XJ6 carried on the grand tradition of Jaguar sedans that began over a half-century before, a tradition most enthusiasts would say is worth preserving.