Category: Large Executive 
Price Range: £84,735 to £86,935
Comfortable, quick, relatively economical, well built.
Expensive, steering lacks feel.
A refreshingly forward-looking take on the classic executive saloon formula.
The differences between the long- and regular-wheelbase versions are barely noticeable on motorways, where the multilink adaptive air suspension makes any LS feel supremely comfortable, relaxed, refined and quiet. But the differences quickly became apparent when you're manoeuvring in town or enjoying yourself on a twisty road. In these circumstances the LS600h L soon feels not just longer but also heavier and slightly clumsier, and try as they might the electronic driver aids and parking sensors can't turn this big, heavy car into something more agile.
It's a different story with the regular LS600h. The 120mm and 250kg-plus advantages play a part, but the secret weapon is the active stabiliser system - a hi-tech form of anti-roll bar, available only on the standard-wheelbase model. It results in far less roll through the bends, which helps the driver feel in control rather than at war with the Lexus. In both versions the electronically assisted steering system is precise, if lacking in feel and feedback, but the shorter-wheelbase car feels more willing to attack a bend with vigour. Whereas the LS600h can look a 7-Series or XJ in the eye, the long-wheelbase version has some of the heel-dragging tendencies of the Audi A8.
When you accelerate you can hear a muted roar from the 5.0-litre V8 engine, which is a development of the 4.6-litre unit in the LS460 with its clever variable valve timing and two fuel injectors per cylinder, and at speed you notice some wind noise, but you rarely hear any droning from the big, grippy tyres on the 19" alloy wheels. We're assured that the new Torsen four-wheel drive system in the 600h is surefooted on ice, but we've not yet been able to test that claim. Blame global warming.
The back seats of the long-wheelbase model are living-room comfortable, backed up by a refrigerated drinks cabinet, footrest, choice of massage options, and the world's first in-car body temperature sensor. There's also plenty of room in the back of the standard version, but the increase in driving pleasure offered by the shorter car means you're likely to prefer being at the wheel.
The '600' in the name is intended to imply that the combination of 5.0-litre V8 and electric motor gives performance equivalent to that produced by a conventional 6.0-litre petrol or diesel engine. It does 0-62mph in 6.3 seconds, which is 0.6 slower than the LS460, and 0.8 slower than the BMW 760i, but midrange acceleration is the real strength of the 600h over the 460: 50 to 75mph in 4.3 seconds versus the 460's 4.7.
On the road it certainly feels quick, and keeps plenty in reserve for high-speed overtaking. And it has the brakes to match, with the slight hesitation of the 460's stoppers now replaced by a beefier system that incorporates regenerative braking, feeding the battery with energy that would otherwise be wasted.
The powertrain is capable of running on just the 389bhp V8 engine, just the 221bhp electric motor (but only at low speeds and for short periods), and a combination of the two. The ability to mix and match the power source to suit the conditions results in fuel consumption figures that are good for a car of his size and performance. The official combined consumption figure is 30.4, which compares very favourably with the 375bhp LS460's 25.4 or the 760i's 21.2.
The clever bit of the LS600h is its power split device, which features a differential-type planetary gear set. It's connected by one output shaft to the generator and by another to the electric motor and the wheels. It's integrated with an electrically controlled continuously variable transmission with eight steps, which can be changed sequentially by hand or left to shift automatically. The driver can also choose between three different suspension modes for a more or less sporty feel.
