Used 2008 Mercedes-Benz CLS-Class CLS63 AMG

Mercedes-Benz strays from the norm with this sleek "four-door coupe." The CLS550 and high-performance CLS63 AMG blend the sexy lines of a sport coupe with the convenience of a luxury sedan.

Mythology is filled with half-this, half-that creatures. A minotaur was half man, half bull. A mermaid was half fish, half hot babe. On South Park, Al Gore dreamt up the fearsome ManBearPig. The 2008 Mercedes-Benz CLS-Class follows in this tradition: a "four-door coupe" that blends the sleek lines of a luxury two-door with the practicality of a sedan. Thankfully, there's nothing mythical about it.

Underneath its sexy tapered roof line and taut curves is essentially a modified E-Class. It's longer than the E, but weighs about the same. The standard semi-active Airmatic suspension that automatically adjusts to reduce pitch, dive and roll during braking, accelerating and cornering makes this four-door live up to the coupe requirement of being fun to drive. Further aiding that endeavor is the CLS550's 5.5-liter V8 sourced from Mercedes' S-Class flagship, and the CLS63 AMG's Herculean 6.2-liter V8 that produces 507 thunderous horses. Both engines are enough to propel the CLS up to speeds that put some sports cars to shame.

While this Benz's four doors certainly provide a practical advantage, as with most coupes, there are downsides in its everyday livability. Those narrow slit side windows and sleekly raked windshield make visibility a precious commodity, while ingress and egress is more difficult that in most sedans. Despite boasting 2 more inches of rear-seat legroom versus the E-Class, the CLS' fastback-like roof line chews into rear-seat headroom -- 6-footers and minotaurs may feel a bit crunched.

The CLS' specialized nature has yet to be copied by any other luxury automaker. As such, it doesn't really have any natural competitors. Besides having a different body style, the CLS550 is more powerful and more expensive than the similarly sized BMW 550i and Audi A6 4.2. The CLS63 AMG lines up better with the BMW M5 in terms of power, though Mercedes' own E63 AMG provides nearly identical performance in a more traditional, practical sedan shape. The S-Class is also in the same price neighborhood, but is obviously a much different animal.

For those who love coupes but find loading kids or grandma through single side doors a rather aggravating experience, the 2008 Mercedes-Benz CLS-Class provides a solution with its combination of high-performance engines, sexy styling, finely tailored interior furnishings and four doors. Some may argue it's a vehicle that's not sure what it wants to be, but like mermaids and ManBearPig, it's hard to deny that this half-breed is a pretty cool creation.

There are two models within the2008 Mercedes-Benz CLS-Class line: the CLS550 and CLS63 AMG. The CLS550 comes standard with luxury-oriented features such as 18-inch wheels, a semi-active air suspension, a sunroof, a power tilt-telescoping steering column, 10-way power front seats with memory, leather upholstery, four-zone climate control and a Harman Kardon Logic7 surround-sound system with six-CD changer, satellite radio and an auxiliary audio jack. In addition to its various performance upgrades, the CLS63 AMG adds 19-inch wheels, heated front seats, upgraded leather upholstery with Alcantara inserts and a sport steering wheel. Many of the CLS63's AMG styling upgrades can be added to the CLS550 with the AMG Sport Package. The CLS63 AMG can be made even more aggressive with the AMG Performance Package, which adds a limited-slip rear differential, a speed governor increase to 186 mph, a track-calibrated suspension, upgraded brakes, upgraded 19-inch wheels and carbon-fiber trim.

Available on both trims is the Premium I Package that adds heated front seats (CLS550), active ventilated front seats, Bluetooth, a power trunk closer and a navigation system. The Premium II Package includes those items, along with keyless ignition and entry and active bi-xenon headlamps. Stand-alone options include upgraded napa leather upholstery (CLS550), active cruise control, parking sensors, iPod integration and run-flat tires (CLS550 only). Also available is a special Designo Graphic Edition (late availability) that includes Graphic Metallic exterior paint and special interior upholstery and trim.

The 2008 CLS550 has a 5.5-liter V8 that produces 382 horsepower and 391 pound-feet of torque. The CLS63 AMG has a 6.2-liter V8 that makes 507 hp and 465 lb-ft. A seven-speed automatic with Sportronic manual-shift capability is the sole gearbox for both trims. In performance testing, the CLS63 AMG sprinted to 60 mph in a staggering 4.4 seconds -- that's supercar territory. Mercedes claims the CLS550 reaches 60 mph in a still quick 5.4 seconds.

The 2008 Mercedes-Benz CLS-Class comes standard with antilock disc brakes, active front head restraints, stability control, side curtain and abdomen airbags at all outboard positions and a driver's knee airbag. Also standard is the PreSafe system, which, when it senses an impending collision (via rapid braking and steering patterns), automatically tightens up the seatbelts, closes the sunroof and positions the right front seat for optimum airbag protection.

In addition to the prodigious thrust offered by its pair of powerful V8 engines, the 2008 Mercedes-Benz CLS-Class also makes a good showing when the road turns twisty. Left in its default "Comfort" mode, the standard CLS' suspension responds with typical luxury car motions -- soft when it needs to be and stiff enough to maintain complete control at all times. There are two Sport settings designed for more aggressive driving, which tighten things up and deliver a full-on sport sedan driving experience when desired. Unlike some other luxury/sport sedans, the CLS invites you to go harder at every turn. Quick steering, minimal body roll and plenty of grip contribute to that sensation. Stepping up to the 2008 CLS63 AMG kicks the already impressive performance up a few notches, making this four-seat four-door the equal of more than a few exotic two-seaters.

The CLS' coupelike body style means getting into the rear compartment is tricky for 6-footers. Once inside, those taller folks may brush their heads, but plenty of knee and shoulder room keep the rear quarters comfortable enough. The short windows make it feel less airy than a typical sedan, but compared to a traditional coupe, the CLS is legitimately comfortable in back rather than merely passable. A strip of wood trim that spans the dash differentiates the CLS from any of its siblings, along with smaller, but tastefully applied touches of wood and chrome trim throughout.

As is typical of many Mercedes models, the COMAND audio and navigation systems are largely unintuitive even when one spends some time to get used to them. Touchscreen systems in Asian competitors and even the oft-aggravating German point-and-click systems (including Mercedes' own next-generation COMAND) are much better.