Brabus, the well known Mercedes tuner has revealed their upgrade program for the 2011 CLS ahead of its public premiere at the 2011 Geneva Motor Show. 
In terms of boosted performance, Brabus has approached both the CLS 250 CDI BlueEFFICIENCY on which it fitted their ECO PowerXtra D4 kit for an additional 31
hp (22.8 kW) and a peak torque of 560 Nm (413 lb-ft) as well as the CLS 350 CDI BlueEFFICIENCY which can benefit from the ECO PowerXtra D6S
tuning kit.
This plug-and-play kit can be installed in less than 45 minutes enables the Brabus 2011 Mercedes CLS 350 CDI BlueEFFICIENCY so ‘influence’ the desired power through the selected shift
program of the 7G-TRONIC PLUS automatic transmission. When the driver chooses the Eco mode peak torque increases from 620 Nm to 690 Nm (457
to 509 lb-ft) between 1,600 and 2,400 rpm, and when the Sport mode is selected, power jumps from 265 hp (261 bhp) / 195 kW to 313 hp
(309 bhp) / 230 kW at a low 3,600 rpm.
With the Sport setting the Brabus 2011 Mercedes CLS 350 CDI BlueEFFICIENCY sprints from 0 to 100 Km/h (0 to 62 mph) in 5.9 seconds and is able to reach a top speed of 250 Km/h / 155 mph (electronically limited).      
In terms of design the Brabus 2011 Mercedes CLS maintains a discreet appearance, although elements like redesigned bumpers, new side skirts, side vents and rear diffuser with the four custom exhaust pipes give it enough exclusivity.  
Brabus press release :
World Debut at the Geneva Motor Show 2011
BRABUS Tuning for the New Mercedes CLS Coupe
The second Mercedes CLS generation has arrived and in a world debut BRABUS (Brabus-Allee, 46240 Bottrop, phone + 49 / (0) 2041 / 777-0, fax + 49 / (0) 2041 / 777 111, Internet  presents an exclusive tuning program for the new four-door coupe at the Geneva Motor Show 2011.
Sporty-elegant design paired with aerodynamic efficiency is the trademark of BRABUS. For the new CLS body components were developed in the wind tunnel. They are manufactured in OEM quality from flexible high-quality Pur-R-Rim.
The BRABUS front spoiler is mounted to the production bumper and noticeably reduces lift on the front axle at high speeds. The front can be further upgraded with the BRABUS front apron caps. They feature strikingly styled air inlets and LED daytime running lights, available with either dark or chrome surrounds.
The CLS gets a distinctly dynamic appearance with the BRABUS sport fenders. In addition to gills each side also features a horizontal brace with illuminated BRABUS lettering.
The BRABUS sill skirts give the four-door an even lower, sleeker stance. A useful and appealing added feature is the set of integrated entrance lights that are activated via keyless fob or door handles.
LED lights for safely accessing the trunk in the dark are integrated into the BRABUS rear apron. Custom-tailored cutouts in the new rear apron provide the perfect backdrop for the four tailpipes of the BRABUS sport exhaust system. The rear appearance is rounded out with a centrally mounted reflector.
The BRABUS rear spoiler creates a perfect aerodynamic balance and emphasizes the sporty character of the BRABUS designer suit.
Another important contribution to the exclusive BRABUS look for the new CLS comes from the BRABUS Monoblock wheels in sizes ranging from 8.5Jx17 to 10.5Jx20. The OEM-quality alloys are available as one-piece and three piece wheels in six different designs.
The most exclusive version features BRABUS Monoblock VI, E or S wheels in size 9Jx20 in front and size 10.5Jx20 in back. The latest addition to the BRABUS wheel family is the BRABUS Monoblock F wheel. Presented initially as a forged wheel it is now also available as a 20-inch cast wheel, which also celebrates its world debut at the Geneva Motor Show 2011. On the new CLS this wheel can be mounted in sizes 8.5Jx20 and 9.5Jx20, painted a grey “Liquid Titanium” shade. The largest tires supplied by BRABUS technology partners Pirelli and YOKOHAMA for these wheels come in size 255/30 ZR 20 in front and in size 305/25 ZR 20 for the rear axle.
Specially calibrated to the use of sporty low-profile tires are the BRABUS suspension solutions, developed in cooperation with technology partner BILSTEIN. The lineup ranges from BRABUS sport springs for a ride-height lowering by some 30 millimeters (1.2 in.). Sportier ambitions can be met with the BRABUS complete suspension, which combines the ride-height lowering with firmer but yet comfortable damper settings. CLS models equipped ex-factory with the semi-active AIRMATIC air suspension system can be lowered by some 35 millimeters (1.4 in.) with the BRABUS suspension module.
BRABUS offers the world’s most extensive performance tuning program for Mercedes-Benz automobiles. The CLS 250 CDI BlueEFFICIENCY model equipped with BRABUS ECO PowerXtra D4 performance kit delivers an additional 31 hp (31 bhp) / 22.8 kW and produces a peak torque of 560 Nm (413 lb-ft).
For the CLS 350 CDI BlueEFFICIENCY BRABUS offers the ECO PowerXtra D6S tuning kit. The plug-and-play auxiliary control unit can be installed by any authorized Mercedes-Benz dealer or any BRABUS competence partner in less than 45 minutes. This high-tech performance tuning also gives the driver the opportunity to influence power yield via the selected shift program of the 7G-TRONIC PLUS automatic transmission.
In ‘Eco’ mode only peak torque is increased from 620 Nm to 690 Nm (457 to 509 lb-ft) between 1,600 and 2,400 rpm. The maximum power output remains unchanged. If the ‘Sport’ mode is selected manually or activated automatically both peak torque and power output are increased. Maximum rated power output then jumps from 265 hp (261 bhp) / 195 kW to 313 hp (309 bhp) / 230 kW at a low 3,600 rpm. Using this setting, the tuned turbodiesel model sprints from 0 – 100 km/h in just 5.9 seconds. Top speed is limited electronically to 250 km/h (155 mph).
All BRABUS engines are operated exclusively with ARAL high-performance lubricants.
Fully stainless-steel BRABUS quad sport exhaust systems are available for all CLS engine variants. The precision-calibrated exhaust systems optimize power yield and produce a throaty exhaust note.
Exclusive interior design that meets every customer request is a particular BRABUS specialty. The options for the new Mercedes CLS range from appealing accessories to custom-tailored interiors crafted from especially soft and breathable yet highly durable BRABUS Mastik leather and Alcantara.
The ergonomically shaped BRABUS sport steering wheel is available in a variety of leather/wood designs. It provides perfect road feedback and ensures a relaxed posture for long-distance driving.
Scuff plates with illuminated BRABUS logo or the speedometer with 340-km/h dial (213 mph) add individual highlights as do the distinctly sporty BRABUS interior accessories: They include aluminum components such as pedal pads, door-lock pins and shifter, and high-quality clear-coated carbon-fiber inlays for dashboard and center console. BRABUS also offers wood trim in any desired color and grain.
The four-door CLS coupe can also be equipped with a custom-tailored BRABUS multimedia package.

Source: BRABUS