MOTORING / Auto Biography: The Jaguar XJ6 4.0.S in 0-60 seconds

IF A Mercedes Benz purrs like a disk-drive, a Jaguar sounds like a high wind in a big chimney. Ford stakeholding or not, Jaguars have not rationalised themselves into 'world car' anonymity. They have stayed synonymous with a still evocative essence of British motoring. Their big, long-stride engines, traditional materials and relatively high aerodynamic resistance aren't fashionable in an era of nose-diving, computer-contoured executive expresses. If everybody drove a Jag the fossil fuel reserves would be dry by the morning, but these cars constitute a charismatic minority. Some people, demonstrating the theory of relativity, even call them a bargain.

The XJ6 4.0S is the latest version in the long-running XJS series, and at a glance it's hard to distinguish it from its predecessors. But Jaguar's engineers haven't been sitting around waiting for cheques from Ford to drop on to the mat. They've modified the excellent AJ6-type engine with altered camshafts, making that swooshing acceleration note smoother without losing its engaging distant growl, and though the power figures aren't up, the refinement is.

Clearly the mechanical update has been to maintain the edge against such class acts as Mercedes-Benz. But compared to a Mercedes, the Jaguar keeps an old-technology feel, subliminal effects deriving from its brawnier-sounding engine, its gents-club interior and its largely unchanged shape, and, in the case of this test car, a manual gearbox. Don't be fooled by the apparent simplicity though, because in its secure braking, astonishingly agile twisty-road handling and eager responses this is a Nineties car, blending cutting-edge technology with a prestigious racing history.

There are a lot of minor detail changes - new controls for the seats, windows, air-conditioning and mirrors, different badging, coachwork-coloured radiator slats. A standard passenger-side airbag completes an imposing package of safety and performance. Drawbacks are that while the rear bench seat is wide enough to accommodate the congregation of a village church, the knee and headroom is not; and the ambient noise levels aren't especially low on motorways. It's thirsty - such huge reserves of power are unnecessary. But it's great engineering, and great fun.

GOING PLACES: A great engine design, the overhead-cam six-cylinder AJ6, subtly improved for greater smoothness, available with silky auto-box transmission or a crisp no-extra-cost manual box (though you have to stretch for first); 0-60mph in a little under 8.0 secs, slightly quicker 30- 70mph overtaking time. One of the best of power units.

STAYING ALIVE: Excellent build-quality and crash resistance, standard airbag for both driver and front passenger, with self- tightening seatbelts, standard anti-lock braking system. Very good handling, particularly on undulating country roads. An extra pounds 2,000 gets you the sports pack, which tightens the roadsprings and includes a limited-slip differential. The kind of body control that belies the car's size.

CREATURE COMFORTS: Plush and relaxing seats, though a shade more support against side-to-side roll wouldn't have hurt, and driving position cramped, especially for tall people. Driver's seat electrically adjustable in all directions, though switch bank awkwardly placed. Door-positioned switch to pull the seat back on entry. Simple-to-operate and effective air conditioning, comfortable ride, but rear leg and headroom ungenerous. Boot deep rather than long, because of upright spare wheel. Not as quiet as some luxury cars, but utterly silent operation is an un-Jaglike quality.

BANGS PER BUCK: High level of features for the outlay by luxury-limo standards, including leather seats, excellent remote locking system (engine immobiliser available as an extra), alloy wheels, improved air conditioning, trip computer. Price: pounds 34,950.

STAR QUALITY: It's a Jag. That means fine engineering allied to a traditional look that hasn't dated.

TURKEY QUOTIENT: Noisier than buyers in this market might expect, thirsty, not roomy enough in the back.

AND ON MY RIGHT: Lexus LS 400 4.0 ( pounds 36,990): a real Merc rival with its remarkable quietness and rugged construction, not up to the Jaguar across country, but very refined, great value; BMW 740i ( pounds 43,950): not as smooth, and a lot more money, but still the top contender for the sportier upmarket buyer; Mercedes 400SE ( pounds 54,650): check the price] The S Class isn't as pretty as the Jag, but it's an engineering and ergonomic masterpiece.

(Photograph omitted)