All CLS variants use the 7G-Tronic automatic gearbox, now in its Plus version with electronic mapping that shifts up early when in "E" mode to maximize economy, as well as working with the standard ECO start-stop system. This is where things start to get complicated for a customer who has just sat down to tick the order boxes. The test cars just had an E-S button on the center console, and that simply chooses Economy or Sport modes for the gearbox and engine mapping.
You can order a sport steering wheel with paddle shifters, which was fitted to our limited edition models. On this wheel, you get M mode when you use the paddles, but the system then defaults back to the chosen E or S mode after a minute or so. To further muddy the waters, you can also order the AMG Sports Package, which features a flat-bottomed AMG steering wheel with aluminum paddles, and an E-S-M button for engine and gearbox modes in place of the S-C-M button on the previous model.
In normal driving, the new V6 is smooth and quiet, and is a refined and economical companion on a long motorway journey, delivering remarkable fuel consumption, along with a 6.1-sec 0-62 mph time.
However, when you extract the full performance of the car, the gearbox seems edgy and sometimes drops two ratios on kickdown. The engine also sounds and feels stressed at high revs, a far cry from the sweet and willing Sport V6 I remember in the SL350, which incidentally is not a lighter car.
Because of this, the CLS350 is not my favored variant. That honor rests with the CLS350 CDI and CLS500. The former boasts 260 hp and 457 lb-ft of torque and a 6.2-second 0-62 sprint.
For keen drivers with deeper pockets, the CLS500, with its bombastic performance and V8 growl, is the obvious choice. Powered by the 4.6-liter, direct-injection, twin-turbo M278 engine first seen in the recently face-lifted S- and CL-Class models, the CLS 500 has 408 hp from 5000 to 5750 rpm and 443 lb-ft of torque from 1600 to 4750 rpm. The new V8's extra 52 lb-ft and 22 percent better fuel economy are strong arguments in its favor. Still in a mild state of tune, it rockets the CLS500 to 62 mph in just 5 seconds. It is smooth and powerful, and has that wonderful V8 soundtrack on tap when you press the accelerator to the carpet. Like all V6 and V8 CLS models, its top speed is electronically limited to 155 mph.
Having just lived with an E500 coupe for a few days the week before, I have to say that the new engine is not as sharp in its response as the M273, nor does it have that hard, almost-AMG edge to it that is a feature of lighter Mercedes M273-powered models like the E500 and SL500. It makes up for this softer edge with a level of torque that leaves any car equipped with the older engine gasping in its wake. With twist peaking at just 1600 rpm, and seven closely stacked gear ratios, you have instant and palpable thrust on demand in any gear.
Where the V6 sounds and feels peaky, and irritates by dropping two gears at a time as mentioned before, the bi-turbo V8 simply thrusts the car down the road with minimal effort and no fuss. At the other end of the scale, a 201-hp CLS250 CDI will eventually appear in the price lists. This will be the first time Mercedes has ever offered a four-cylinder in the CLS range, but with the advent of the S250 CDI, it seems that anything is now possible.
While Airmatic suspension is standard on the V8 model, it is an option with other engines. As before, Airmatic automatically lowers the ride height by 15 mm over 62 mph irrespective of whether the suspension is in Comfort or Sport mode. In Comfort, the preferred mode for wafting along motorways, the car has a very high degree of ride comfort on all road surfaces, even with 19-inch wheels.