A new family of engines, including higher performance AMG versions, heralds the arrival of the next generation Mercedes CL coupe and revised S-Class saloons in showrooms from October.The new generation of modular V8 petrol and V6 diesels build on the BlueEfficiency principles with sophisticated high performance ignition.By re-designing and manufacturing the engines to reduce friction, MB has managed to significantly raise power outputs, cut fuel bills by a quarter and emissions by about the same depending on the model.The newest engines also benefit from stop & start function and the latest 7G-Tronic plus automatic transmission.In the case of the S and CL 500 BlueEfficiency powered 4.6V8, the 435hp petrol models show gains of 12pc more power, torque is up almost a third and consumption is down 22pc - all remarkable achievements in cars of their size.The CL63 AMG V8 new engine has been completely retuned above the standard unit to punch out 544bhp, with sharper responses calibrated into its electronics and 7-speed transmission. This bi-turbo now outperforms the naturally aspirated 6.2 litre of the former 63-AMG coupe and saloon.The new engines' modular design suggests they are the beginning of a new family of power units from the car maker and they have been designed from the outset to be part of any hybrid powertrain in future. EquipmentMB has introduced additional technical features including active lane assist, blind spot monitors, radar and camera assistance systems and even cross wind stabilisation, which uses sensors on the suspension to measure cross-wind hitting the car from any direction and then beefing up the resistance within in milli-seconds.The new CL has a dramatically different front end incorporating new grille, headlamps, bumper and bonnet and LED daytime lights, and there are new tail lights.The rear deck rolls over the wings in a more continuous line and the coupe roofline is different. Inside there is the latest split view technology using thin film transistor which allows driver and passenger to simultaneously view different displays, as well as powerful navigation and sound packages.The best selling year for the CL Class in the UK was 2007 when 729 went through dealerships but the arrival of the recession halved that figure the following year and it slipped further again last year and to date in 2010 has just topped 100 units. The arrival of the new CL is expected to see sales start climbing again.Mercedes CL and S Classes product manager Claire McAlistair said, 'We expect renewed interest in these cars thanks to their much greater fuel efficiency and increased performance combined with tremendous technical features. The latest engine technology will transform the driving experience for users and put us at the forefront of people's minds.'The new CL500 BlueEfficiency will cost £89,425 and the CL63 AMG goes from £111,985, representing average rises under 3pc.In the revised S-Class, the new 350 3.0V6 diesel will replace the outgoing 350 CDI with more outright power, torque, lower emissions and consumption. At best it gives 41.5mpg and emits 177gkm, one of the cleanest and most economical diesels, and means it already meets the 2014 EU6 standards.Visually the latest S-Class gets minor cosmetic changes to the front end and integrated rear tailpipes.Mercedes has included more standard equipment such as the multi-function media interface and top versions have a new Bang & Olufsen system which combined add more than the 1.6pc price rise introduced with the changes.The latest S350 BlueTec enters the range at £58,440, the S500 4.6V8 begins at £79,810 and the S63 AMG is £109,125. First impressionsAt a piston-stroke, the newest engine range moves Mercedes higher up the desirability stakes.It is quieter, much smoother and delivers power more readily, economically and cleanly. It's a win-win formula.With the stop-start on the S-Class you do not have to make a conscious decision to make it work once you have selected the Eco mode and it responds immediately without any worrying delay which can cause panic in heavy traffic.The big S-Class provides excellent ride and room but with it comes a more refined powertrain as well for the second decade of the 21st century and the model series celebrates its 60th year of production.Turning to the better selling CL-Class, the new model is immediately visually different and refreshed while under the bonnet and inside its new technology makes it more of a driver's car as well as being a genuine four-seater coupe. Access to the two rear seats is easy and once inside the leg and headroom is very good.The CL63 AMG is a delightful blend of performance with panache, delivering immense urge immediately when called upon and without challenging the driver to push their limits. Mercedes-Benz CL500 MILESTONES Mercedes-Benz CL500 BlueEfficiency Price: £89,425.Engine/transmission: 4.6-litre V8, bi-turbo 435bhp, 700Nm of torque from 1,800rpm, 7-speed, automatic.Performance: 155mph, 0-62mph 4.9 seconds, combined consumption 29.7 mpg, CO2 224g/km, VED Band L road tax £750 first year rate then £425 second year onwards, BIK company car tax 35%.Insurance group: 50E.For: : Restyled, very roomy coupe, refined powertrain offering excellent performance and economy potential and very quiet.Against: : Expensive to buy, tax and insure, complex multi-media system distracting to use, some steering vagueness.