New engines trigger model-name changes for Mercedes' 2007 CLS sedan. Essentially an E-Class sedan in sleeker sheetmetal, CLS seats four vs. the E-Class' five, and does not offer all-wheel drive or a wagon body style. Two models are offered. The CLS550 has a 382-hp V8 and replaces the 302-hp CLS500. The high-performance CLS63 has a 507-hp V8 and replaces the 469-hp CLS55. Both have a 7-speed automatic transmission. Steering wheel shift buttons are optional on the CLS550, standard on the CLS63.

Both have an air-spring suspension that adjusts firmness within three driver-selectable modes. Traction/antiskid control is standard, as is antilock braking via Mercedes' "by-wire" control that can adjust brake pressure for each wheel. The CLS63 adds firmer chassis tuning and cosmetic touches by Mercedes' AMG performance division. An AMG Sport Package for CLS550 includes wider tires and aero body trim. Front and rear side airbags and curtain side airbags are standard. So is a full-length center console and twin bucket-type rear seats. Available are steering-linked bi-xenon headlamps, navigation system, and keyless locking/engine-start with pocket transmitter. This evaluation is based on preview test drives.