Hydropneumatic suspension :-) There's a hydraulic pump about the size of a coffee cup driven off the end of the camshaft, which provides power to the suspension, braking system, and steering.

The suspension has no springs or shock absorbers - there's a "sphere" screwed into the end of each suspension cylinder with a bubble of nitrogen trapped by a rubber sheet that acts as a spring, and a set of spring-loaded valves kind of like the ones in a shock absorber piston to set the damping rate.

For the brakes, the hydraulic pump fed the ABS block through a shuttle valve under the pedal. When you press the pedal it does not move! Or, hardly at all. I takes a little getting used to and the brakes feel really harsh until you realise you don't need to welly it down hard - just gently touch it. The back brakes use pressure from the rear suspension, so they're more effective the heavier the car is.

The steering is amazing. When the engine is running the road wheels and steering wheel are not really connected. There's a linkage through a shuttle valve and when you turn the steering wheel it acts as a servo, with the wheels being moved entirely by hydraulic pressure. The Danfoss valves in normal power steering systems work a bit like this but they use a bendy spring, and the hydraulics only "help".

To make it respond properly at speed there was a heart-shaped cam in the steering box, with a sprung piston pushed into it by hydraulic pressure from a speed governor on the gearbox. The faster you go, the more pressure on the piston, and the harder the spring presses a roller into the cam. At idle with the car stationary you can move the steering wheel and it'll spring back to the middle by itself, and at 70mph you can barely move the steering wheel at all.

It's really sensitive and the first time you drive one you find yourself zig-zagging down the road until you get used to just leaving your fingertips on the rim of the wheel and basically just touching the side you want it to turn to.

They're not terribly fast but you can gobble up the miles surprisingly quickly, and I've never driven anything where you arrived so relaxed.