In the cabin
The cockpit of the SL550 is a triumph of spartan sportiness over luxury. Aside from a sliver of wood in the center console and $900 worth of timber on the steering wheel and shifter, the appointments are a mix of black leather covering the seats, cowl, and the doors; and black plastic trim for everything else. For those with an extra $7,850 to burn on finery, the SL550 does come with three designo trim packages (Espresso, Mystic White, and Graphite), which give the car an upgraded paint job, some Nappa leather appointments, a wood-and-leather wrapped steering wheel, a roof liner, and some designer floor mats.
The most dramatic tech feature of the cabin is its retractable hard-top roof, which opens and closes with the aid of a flap located toward the rear of the center console. With a pull of the flap, the roof majestically folds up and disappears into the trunk in about 15 seconds. Our test car came with the Panorama roof option, which replaces the standard roof with a glass panel, letting more light into the cabin and giving the car a more flowing rear profile. With the roof in the boot, the SL550 has an impressive amount of cargo space left available, which is made particularly accessible by a tilting shelf that swivels upward when the trunk is opened to allow access.
Waiting for the top to come down gave us an ideal opportunity to program the SL550's dynamic multicontour seats (part of the $3,150 Premium I package). This function gives both occupants the ability to adjust their seat's shoulder width and lumbar support via a cluster of buttons located on the outboard side of the seats. In addition to fine-tuning the seat's pneumatic chambers to suit your posterior's requirements, the multicontour controls include a Pulse feature designed to alleviate lower back fatigue.
The GPS navigation system in the SL550 comes as standard. As has been the case in other Mercedes models we have reviewed for the 2007 model year (the 2007 E550, 2007 E320 Bluetec, and 2007 GL450 spring to mind) we are less than impressed with its design and usability. The system is not a touch screen, so destinations have to be input using a four-way cluster of buttons on the bottom right of the unit. Programming the system is intuitive but time-consuming, and it can be frustrating waiting for the lag that accompanies each stage of information entry. Another gripe is that the system asks for confirmation for city and street entries twice, which can get annoying.
With a destination entered, the SL550 takes about 8 to 10 seconds to calculate a route and to commence spoken voice guidance. Although the system doesn't include text-to-voice technology for reading aloud individual street names, it does display the name of the upcoming street and a large blue turn arrow when approaching turns. However, there appears to be no way to turn up the volume of the voice guidance other than twisting the volume knob at precisely the same time that the turn-by-turn directions are being enunciated.
The SL550 comes with a single audio system option in the shape of an 8-speaker Bose Cabin Surround setup, including a separate subwoofer. Acoustics are as immersive as one would expect with so many speakers in such a small space, and with the top up, the Bose Audiopilot digital processing does its job by compensating for ambient noise. However, despite the audio system's impressive sounding specs (proprietary channel assignment algorithm for a balanced, accurate surround-sound experience; independent front and rear channels for a 360-degree sound field) the reproduction of the system itself is nothing spectacular: bass can sound muddy and dull and the defined highs demanded by the Sirius Symphony channel can come across as shrill. The main drawback with the stereo system is the placement of its 6-disc changer. Not only is this located rear of the two seats, requiring the car to be stopped for the driver to change the music selection, it is placed directly behind the driver's seat. This means that, in the absence of a passenger, the driver must either perform some extensive bodily contortions or get out of the car to eject and reinsert the cartridge.
Topping off our list of complaints with the audio system, there is neither an auxiliary input jack nor an optional iPod adapter available on the SL550. The picture does not get any better, so to speak, for video playback. While the SL550's manual advertises that the car's entertainment system can be used to play DVDs, the system locks out the visuals from any movies that are inserted into the disc slot--even when the car is parked and the engine is off. If you are happy listening to the soundtrack of your favorite films when driving, this is nice feature; if, however, you prefer your DVDs with visuals, this system is of limited value.
We do hate to harp on, but hands-free calling is another disappointment on the SL550 (just as it is on all other new Benzes). The standard phone cradle works with only five cell phone handsets, forcing owners of other phones to invest an extra $408 in an add-on Bluetooth module in order to make hands-free calls. This is a bitter pill to swallow on such an expensive car, especially since Bluetooth hands-free calling comes standard on many cars less than half this price. Having coughed up for the Bluetooth module, drivers can then spend an extra $500 on voice control, which enables control of the hands-free system and audio system by spoken command.
If we were pushed to make a positive observation on the interior design of the SL550, it would have to be on the pop-out cup holders, which we favor emphatically over the stick-on effort in the 2006 BMW M6.
Under the hood
As we found in our practical driving test, the SL550 is not an overwhelming performer, but it is very quick and well-suited to its mission of status-mobile. When called into life, the 5.5-liter V-8 can feel dilatory, but this is soon overcome north of 2000rpm as the car squirts forward with real pace. The SL550 delivers an extremely smooth, quiet ride. Even with the top down, the car will hum along at freeway speeds without translating much road- or wind noise into the cabin. With the top up; the ride is impressively quiet, the only interruption being a bossy note from the exhaust when accelerating.
Like the other cars we have tested with the flagship Mercedes engine, the SL550 comes with a driver-adaptive 7-speed automatic transmission with Touch Shift manumatic override. When left to its own devices, the automatic transmission features driver-adaptive programming, which apparently adjusts the car's shift points to match the driver's current driving style. We have to say that we could not tell if our driving style was being matched or not, although throughout a range of driving styles, the car never felt like it was hunting for gears, so something must have been working right. Other niceties of the gearbox are its Shift into Optimum Gear function, which selects the best gear for maximum acceleration or engine braking; and Comfort mode, which starts the car from second gear when pulling off and upshifts at lower rpms--ideal for those Sunday morning cruises.
Our storm-red 2007 Mercedes-Benz S550 came with a hefty base price of $94,800 to which we added $3,150 for the Premium I package (ventilated- and dynamic multicontour seats, bi-xenon headlamps, corner-illuminating fog lamps, Keyless Go); $1,920 for the Panoramic roof with sunshade; $900 for the wood-and-leather-trimmed steering wheel and shift-knob; $510 for the electric trunk closer; $775 for destination and delivery; and a $1,700 gas-guzzler tax. All told, it came with a sticker price of $103,755. For that price, you are in seriously competitive territory. For the same money, you could get yourself a BMW M6, or a 2007 Jaguar XK with $30K left in your wallet.