Used 2007 Mercedes-Benz SLR McLaren

What do Paris Hilton and Formula 1 World Champion Fernando Alonso have in common? Both have owned a Mercedes-Benz SLR McLaren. Actually, Hilton handed hers back after a couple of "incidents."

This joint patronage of the Mercedes flagship strikes at the paradox at the heart of the 2007 Mercedes-Benz SLR McLaren Roadster. For all Mercedes-Benz's talk of F1-derived technology, McLaren know-how and outrageous performance, the SLR has always been a different type of supercar than the Ferrari Enzo or Porsche Carrera GT. With its automatic transmission and all-around civility, the SLR has been perceived as a car for poseurs, not pole-sitters.

The new SLR Roadster invites further comparison to celebrity jewelry, but there's talk of subtle improvements beneath the new canvas convertible top. An uprated carbon-fiber monocoque promises open-air speed without the dreaded shakes, and different dampers are meant to improve the car's occasionally wayward handling.

Could it be that in its latest (and perhaps final) iteration, the 2007 Mercedes-Benz SLR McLaren Roadster finally delivers a drive worthy of the McLaren badge?

Always a Vision of Top-Down Speed
The idea for an SLR Roadster is nothing new. When Mercedes first revealed the Vision SLR concept in 1999, it showed both a coupe and a roadster. The coupe appeared as a production car in 2003, the track-ready 722 model followed last year, and now the SLR Roadster goes on sale this fall. "We wanted to do the coupe first because we wanted to draw a clear association with the world of GT racecars," says Klaus Nesser, the man in charge of the SLR and Maybach vehicle programs.

Like the coupe, the Roadster remains true to the original concept. This is a source of pride, but also a clue to the car's early problems. The McLaren engineers freely admit that the show car's aerodynamics were awful. In order to create a car capable of 200 mph, they had to engineer a flat underbody culminating in a dramatic rear air diffuser and then add an active rear wing. Even then, the rear end of the car felt disturbingly light at very high speed.

For many SLR owners, such imperfections have been a small price to pay for a shape that is pure theater. The SLR has a sense of occasion that no modern Ferrari other than the Enzo can match. The SLR Roadster enhances the glamour with its sleek, roofless shape, as the electrically powered fabric top stows neatly behind the front seats, leaving intact the car's trademark scissor doors.

Once More With Feeling
The cabin is shared with the coupe, which is a mixed blessing. There's some nice detailing — the instruments look terrific and Mercedes must use supermodel cows for the leather — but too many of the plastics feel low-rent. The SLR flap that hides the stereo is naff and the CD-based satellite navigation system feels like a 1990s throwback. After all, you expect more for a half million dollars.

Cabin space is also tight. The carbon-fiber seats can be specified in several different sizes, but even if you find one to fit your derriere, anyone taller than 6 feet will want for legroom.

At least your luggage will be well catered to. Even with the convertible top folded down, there's a useful 7.1 cubic feet of trunk space — enough for a weekend away.

It's Got the Power
The protocol for starting the SLR's engine is straight out of a James Bond movie. You flick open the cover on top of the shift lever. Prod the starter button beneath and it glows red as 5.5 liters of supercharged V8 spring to life. Developed by AMG, this is one of the world's great engines.

A huge volume of air — more than 2 tons per hour, Mercedes tells us — is sucked through the three-pointed star on the front grille, compressed by the belt-driven supercharger and stuffed into the V8. The supercharger is mounted on an aluminum brace because the heat it produces would decompose a carbon-fiber piece.

The V8's output figures are otherworldly. The 617 horsepower at 6,500 rpm makes headlines, but let's not forget the 575 pound-feet of torque available from between 3,250 rpm and 5,000 rpm that really determines this car's character. This real-world power is what distinguishes the SLR from supercars such as the Ferrari 599 (448 lb-ft) and Lamborghini LP640 (486 lb-ft).

The mighty torque is also why the SLR works so well with an automatic transmission. Shared with the Maybach, this automatic requires just five widely spaced ratios to take this car from zero to 206 mph — a top speed just 1 mph less than that of the SLR coupe. The transmission has Sport and Comfort modes, and the shift paddles on the steering wheel do the work.

Power and Style
In some ways, the SLR is a throwback to a bygone age. The rich, melodic sound from the quartet of side pipes recalls an old Can-Am racecar. You find yourself playing the throttle like a musical instrument, thrilled as the engine revs melodically rise and fall.

Of course, the SLR Roadster is brutally quick. Mercedes claims 0-62 mph (100 kph) in 3.8 seconds and 124 mph (200 kph) in just 10.9 seconds, and you can achieve them just by extending your right boot and hanging on. On an unrestricted but busy autobahn, we briefly saw 186 mph, and the Roadster accelerated above 100 mph much like a Porsche 911 does between 50 and 100.

With the top down, the Roadster is also remarkably civilized. A tiny screen between the seats helps minimize the buffeting and the cockpit is not uncomfortable, even at three-figure speeds. To compensate for the structural rigidity lost with the roof, Mercedes added another layer of carbon (it's now tri-axial) to the tub. The result is a car with almost no scuttle shake, even on bumpy surfaces.

Driving the Blitzen Benz
Yet for a true driving enthusiast, the SLR is still something of a disappointment. There is nothing wrong with the stopping power of the brake system's ceramic discs, but there's little pedal feel, and it seems as if you are pushing against an artificially weighted brake booster. As a result, it's difficult to modulate braking effort — a key concern in a car this fast.

There's plenty of mechanical chatter through the steering, but it tells you little about what the front wheels are up to. It is also too reactive. Instead of making single, measured inputs, you find yourself instinctively making lots of little corrections throughout a turn. We've driven almost 3,000 miles in various SLRs, and the steering still undermines our confidence.

Since the SLR's introduction in 2003, Mercedes has replaced the original Bilstein dampers with Koni units in a bid to improve the car's high-speed stability, and there is an improvement. But although the SLR has a surprisingly cosseting ride for such a sharply focused performance car, the balance between comfort and command still isn't right, perhaps because 200-mph capability compromises feel and sensitivity.

Poseurs, Not Pole-Sitters?
It's no secret that the relationship between McLaren and Mercedes was strained during the development of the SLR. McLaren's desire for ultimate performance didn't prove perfectly compatible with Mercedes' insistence on civility, safety and practicality. Significantly, no member of the McLaren team was present at the introduction of the 2007 Mercedes-Benz SLR Roadster.

For a car that's likely to cost $500,000, the SLR Roadster is too compromised. A Porsche 911 Carrera is a more satisfying drive, and a Ferrari 599 is in a different league. But we suspect that for the 1,100 or so people who've already bought an SLR, the subtleties of steering and braking feel don't matter a jot.

For drivers like these, the Roadster will simply enhance the SLR's appeal as one of the most spectacular, theatrical cars of this or any other generation.

Edmunds attended a manufacturer-sponsored event, to which selected members of the press were invited, to facilitate this report.