This set-up inserts a 21bhp, 184lb ft electric motor between the engine and the nine-speed automatic gearbox. It seamlessly starts the petrol engine, augments take-off and acceleration, can help the car coast, engine-off, in its economy setting, and converts itself to a generator to feed retardation power back into the battery on the overrun.
On the performance front 0-62mph acceleration is timed at 4.5 seconds and top speed is a governed 155mph; in real-world driving you’ll easily turn 32-34mpg and 38 if you try hard. Which makes Mercedes’s combined figure of 31.7mpg figure look more honest than most. The 203g/km CO2 output isn’t too shabby, either.
The performance is effortless, partly because the electrically boosted power and torque don’t have lags or gaps, and partly because the nine-speed ’box provides a profusion of low, easy shifting ratios especially in the early acceleration phase. You can control the gearbox by paddles if you want, but with a Sport setting selected, you’ll soon get the feeling that the gearbox makes sophisticated decisions often better than your own. Only the need for engine braking on long slopes encourages you consistently to use the paddles.
This is a heavy (2.1 tonne), long wheelbase car, so it’s not the kind of thing you chuck about. The standard 4Matic drive system (which in all but low-grip situations allows the car to behave as a rear-wheel drive Merc) and the slightly too intrusive electronic stability controls keep it very firmly in line. However the E53’s steering weight and accuracy makes it surprisingly simple to place, and with the right chassis settings it grips beautifully, corners neutrally and practically refuses to roll on bends. The 4wd system causes some intrusive tyre scrub at low speeds on concrete surfaces, but you get used to it. The brakes (increased in size as part of AMG’s work) are very powerful and intuitive.
Seekers of last-word luxury may not like the word: even in Comfort this big estate is stiffer and sportier than most peers. My own choice, 85% of the time, was the Sport setting, though I soon learned how to locate the Dynamic button by feel (for UK buyers it’s on the wrong side of the HMI selector wheel) to calm the ride over extended ruts. Most of the time, though, this is a pleasant, fairly sporting, fast and long-legged machine with generous space in its cabin, well capable of extended trips for four people and generous amounts of luggage. It’ll make quite a lot of AMG-style noise with its exhaust and induction system if you give it the beans, but these never seem to intrude unless you want them to.