It doesn't seem so long ago that we were making sniffy noises about the original S-Type being rather too "Hollywood" in its interior presentation, although that may have seemed OK for the important US export market. The interior has long since been altered to be rather more traditional Jaguar in appearance, and has recently been revised again, but the really notable thing about the mid-2004 range is that it includes a really top-class turbo diesel engine.Saying to a Jaguar person, "Oh yes, that's the Peugeot 2.7-litre, isn't it?" is the kind of thing which leads to a modern motoring equivalent of the P G Wodehouse line: "Ice formed on the butler's upper slopes."The engine is indeed the first fruit of the joint PSA/Ford project to design and produce a twin-turbo diesel V6 for Ford, Peugeot, Citroen and - in Jaguar's case - brands within Ford's Premier Automotive Group portfolio, but Jaguar is the pioneer make here, and was able to make detail modifications to the basic engine to suit its own requirements.Just as Jaguar is paying attention to overall body weight - the latest S-Type has an aluminium rather than steel bonnet, for example - so the team which designed the new V6 turbo diesel engine made it as light as possible. It weighs in at only 202kg, lightest diesel engine in the class, and no more than 15kg heavier than the corresponding petrol V6.It's also a genuinely state-of-the-art design. Diesel enthusiasts can wallow in descriptions of the variable swirl intake system, and the toroidal combustion chambers in the piston crowns, but the simple message is that this is a 2.7-litre with very impressive performance, economy and emission figures, throttle response and flexibility.The SE turbo diesel is fitted as standard with a six-speed J-gate automatic, not quite able to match a six-speed manual's acceleration, fuel consumption or CO2 rating; but, as market observers are fond of saying, at trade-in time it's a lot better to have any kind of automatic Jaguar, because there will be many more hopeful second owners wanting one of those than are interested in a manual.As well as installing this excellent engine, Jaguar has tweaked the S-Type suspension by altering the mid-2004 cars' spring rates and damper settings, but the SE still has what Jaguar likes to call "touring" suspension. That's fine, because even wearing SE rather than Sport badges the turbo diesel feels really well-balanced, and a sporting saloon in its own right. It's not a matter of this long-striding car being at home only on motorways. Out on country roads it's unexpectedly agile, and when you want a blast of hillclimbing or swift overtaking there's 320lb/ft of torque from 1900rpm to slingshot you on your way.Some quite mild exterior styling changes, and more attention to close panel fit, have freshened up the outward appearance. Inside, there's a new instrument display and one or two other changes, but the SE stays faithful to the traditional wood and leather approach Jaguar does better than anybody else in this class.A number of critics say that this leather and burr walnut stuff is just too 20th-century, but I've never seen the sense in that. If Jaguar went techno, the passenger cabin wouldn't have the same appeal. Mind you, there is a subversive element within the company which has allowed aluminium fascia trim to appear in the latest S-Type Sport and R models, although SE buyers don't have to worry about that.The S-Type, of course, is the Jaguar whose exterior styling is supposed to be something like a modern take on the "Inspector Morse" Mark 2, and none the worse for that. It offers pretty good rear cabin space, although a little more foot room under the seats in front would be welcomed by rear-seat passengers.Standard items in the SE include eight-way electrical adjustment for the driver's seat, while the front passenger does not badly with six-way. Heated seats are on the extra-cost options list, along with the likes of a fixed cell phone, adaptive cruise control, an electrically operated glass sunroof, a CD autochanger and an uprated sound system.There are navigation and headlamp packages, the latter including xenon headlamps with power wash and automatic levelling.Even without dipping into the options and accessories list, the SE is a well-presented saloon, and as tested it certainly comes with appealing dynamics as well as a premium turbo diesel engine. Engine 2720cc, 6 cylinders Power 203bhp Transmission 6-speed automatic Fuel/CO2 36.0mpg / 208g/km Acceleration 0-62mph: 8.6 seconds Top speed 141mph Price £31,670 Details correct at publication date