Performance upgrades to the Airmatic semi-active air suspension include stiffer adaptive damping springs and shocks, a ride height dropped by 10mm, and larger stabilizer bars. To tailor the suspension to specific conditions, the driver can choose between comfort and sport modes, or one in between that combines characteristics of the two. Automatic load leveling keeps the 2006 Mercedes CLS55 AMG on an even keel no matter how many people are along for the ride.

Sensotronic Brake Control, an electro-hydraulic brake-by-wire system that has been troublesome for Mercedes on other models, is standard on the 2006 Mercedes CLS55 AMG. In this application of the technology, the system is upgraded for performance driving with silver-painted calipers (eight-piston front and four-piston rear) that clamp down on internally ventilated and perforated antilock disc brakes measuring 360x36mm up front and 330x26mm in back. Interestingly, the standard stability control system can brake specific inside wheels on corners without reducing engine power, creating the effect of a mechanical limited slip differential.

Calibrated to automatically increase assist levels at speeds under 60 mph and provide greater effort at speeds over 60 mph, the 2006 Mercedes CLS55 AMG's power speed-sensitive steering is able to supply easier parking and in-town maneuverability while also optimizing road feel and control. Five-spoke AMG wheels measure 19 inches in diameter and wear 255/35 rubber up front with 285/30 rear tires. Standard equipment includes a tire pressure monitoring system.