Recent years have seen green issues focus the minds of carmakers at all levels. From the smallest supermini to the largest saloon, consumption, emissions and sometimes even weight savings have become major selling points. There is, however, something amusing about a carmaker attempting to squeeze a little more out of its high performance models. After all, no one really considers the green credentials of a 500 horsepower monster before signing on the dotted line. Still, every little move helps. And with carmakers\' group CO2 figures becoming increasingly important in the eyes of regulators, the activity is more than just for show. Mercedes is the latest company to embrace the green movement at the faster end of its model line-up. Its AMG models have been highly praised in recent years, offering an impressive blend of executive-level refinement and hairy-chested performance. Recently AMG\'s 6.2-litre V8 has been the cornerstone of the large car range and powered the popular E63 AMG, but a new 5.5-litre biturbo motor has been introduced. The reduced capacity and decision to turbocharge has ensured that performance remains broadly the same but fuel consumption and emissions have been reduced. It\'s a smart move, and one that ensures everyone is happy: regulators and keen drivers alike. The raw figures only tell half the story. In standard trim the revised E63 AMG produces 525bhp or 557bhp in Performance Pack trim. Complementing these are torque figures of 700Nm and 800Nm respectively. A bonus of the turbocharging is that the peak torque kicks in a lot earlier than before. Dragster-like sprinting behaviour is guaranteed thanks to those figures, and sure enough 100kph can be reached in 4.3 seconds and a tenth less respectively for the uprated variant. Despite all this potential hooligan-like performance, fuel consumption has been reduced from the outgoing naturally aspirated V8 to an impressive 9.8 litres-per-100km for the new saloon. Granted, real world performance will likely see that dip lower, but nonetheless it\'s a good starting point. CO2 is an equally reasonable 230g/km. Theory lesson over, it\'s time for some practical experience. Turn it on and the E63 greets you with a familiar AMG bark, letting you know that it\'s no show pony. The now familiar seven-speed auto transmission can be left in D for most of the time, while the four modes (Comfort, Sport, Sport+ and Manual) offer increasing degrees of shift response, while the latter is accessed via a pair of chunky steering wheel-mounted paddles. On the road the E63 delivers a surprisingly comfortable ride for something with so much potential. The option to switch between two supplementary suspension settings gives you the flexibility to firm things up when conditions allow. Another change from the old car is the switch from electro-hydraulic steering to an electro-mechanical setup. The change appears to have been a good one, with the steering a little lighter at slow speeds — great for town and parking — but offering plenty of weight and feedback when you up the pace. What\'s most obvious, however, is the distinct lack of turbo whistle or lag. Fans of the previous E63 can rest easy; there\'s the same or maybe even more urgency when you mash the throttle with the new 5.5-litre engine, and there\'s no doubt over the car\'s relentless pace given the right conditions. It\'s also encouraging to note that the Performance Pack option really does make a difference. Granted, the power and torque hike is modest but the extra poke transforms the E63 into a genuine supercar challenger — not that the regular car feels wanting. Play around with the various settings and you can get the car to behave or wag its tail like a drifting champion. With the latter progress is always predictable, which is doubly impressive for a car of this size. Playing it straight also reaps rewards; be it a race track or favourite backroad, the E63 is surprisingly agile and feels much smaller than it really is. The car\'s new steering is precise and, even in the firmest setting, the suspension does a good job of dealing with surface imperfections. Mind you, all this technical talk soon goes out the window when you hear the car bellow, pop and cackle its way from A to B. Some rival cars offer a more clinical and precise experience, yet the E-Class on steroids manages to raise a bigger smile from the driver. Verdict The switch to a turbo motor might have reduced the decibel count inside the cabin a little — good for relaxed motorway cruising — but it only takes a quick prod of the throttle pedal to change all that. The result is proof that despite the need to chase down emissions and fuel consumption, the AMG engineers still know how to make fast cars fun to drive. Specs Model E63 AMG (Perf. Pack) Engine 5.5-litre V8 biturbo Transmission Seven-speed auto, RWD Max power 557bhp @ 5,250rpm Max torque 800Nm @ 2,000rpm Top speed 250kph (limited) 0-100kph 4.2 seconds Price TBC Plus Superb engine and gearbox, comfortable Minus Could be louder Rivals BMW M5 The first M5 to feature forced induction, the 2012 iteration packs a twin-turbo V8 engine pushing out 560bhp at the rear wheels. That\'s enough to hurl the sports saloon to 100kph in 4.4 seconds. It\'s 0.2secs slower than the E63 AMG in a straight line, but its cornering abilities would most likely be unrivalled in the segment.