As the crowd starts to slowly slope away, there's the deep explosion of a huge engine clearing its throat. Everyone stops in their tracks and as the initial, luxurious whoomph gives way to a resonant, organ-jangling burble, their heads swivel sharply. The soundtrack fits the Viper's rippling silhouette perfectly, yet the noise is coming from the other end of the car park. The SL55 AMG, which until a few moments ago was nearly invisible, has arrived and it's stolen the Viper's voice.
The quietly menacing SL55 is a very different animal to the brash Viper SRT-10, and yet these two diametrically opposed sports cars are manufactured by the very same international conglomerate, DaimlerChrysler. The Merc is a model of good taste and understatement, lavish where the Dodge is sparse, loaded with electronic devices where the Dodge is deliberately and stubbornly analogue. The thunderous Mercedes has become a part of the motoring landscape now; the natural choice for anyone with £90,000 or so to spend who wants monster power with a deep veneer of civility. The Viper (it's not a Viper in the UK, but SRT-10 doesn't quite have the same gravity, does it?) will never be a common sight at nearly £80,000. Two more different takes on the super-roadster formula are impossible to imagine.
Mercedes' AMG division and Dodge's backroom boys have very probably never met but I'm sure if they did they'd quickly find common ground. How about an unnatural obsession with 500bhp supercar-chasers and heavyweight engineering for starters? Maybe Daimler and Chrysler's unlikely marriage isn't as unfathomable as it seems.
When you do hit the red starter button on the Viper's console, the 8.3-litre V10 churns and erupts. It's a loud, flat, blaring noise with none of the soft loping pulses that make a traditional V8 so appealing. But there's obviously real power lurking under the chiselled bonnet, and the side-exit exhausts, even at a slow tickover, shoot industrial plumes into the air.
Rated at 500bhp and in a car weighing 1545kg, it's no surprise that the Viper feels as ludicrously over-endowed as the pumped-up looks would suggest. First gear stretches to nearly 60mph, second to 90mph and third is good for a faintly absurd 120mph or so. Those long gears help keep the Viper's 345-section rear tyres hooked-up even when you hit full power in second, and such is the V10's urgency and the sheer volume of its voice as it climbs up the rev-range that you naturally find yourself shifting up at around 3500rpm, well short of the 525lb ft torque peak at 4200rpm. That six-speeder is a tight, well-defined gearbox, which makes you want to stir it, even though the 8.3-litre engine renders it almost unnecessary. Wring the Viper out to its near-6000rpm limiter and you're rewarded with flaring wheelspin and a quart of adrenaline rushing through your veins.
Incredibly, the beautifully tailored Mercedes is even more explosive. That 493bhp 5.5-litre V8 has one key advantage over the Viper - a supercharger that feeds the SL55 such rich quantities of air that it gets the drop on the 8.3-litre Dodge and never really looks back. With 516lb ft of torque available from 2650rpm, a fast-acting five-speed auto 'box and instant drive-by-wire throttle response, the 1955kg SL55, subjectively at least, murders the lighter and marginally more powerful Viper.
That the Mercedes has every three-letter traction and stability device known to man plays a large part in the SL55's tangible on-road performance advantage. You feel liberated to jump on the accelerator rather than slowly squeeze on the power, and you're happier letting the supercharged V8 hammer through to the red. The occasional fizzing of the rear tyres and frantic yellow warning light pinging up on the instrument binnacle tell the tale of electronics versus physics (and suggest that the Dodge has the superior mechanical traction), but it's a battle you're happy to let play out and the spoils are delivered cleanly to the rear tyres.
Where the Mercedes rams home its advantage is on your average British A- or B-road. It glides where the Viper crashes, turns-in with confidence at speeds that would have your backside puckering in the big Dodge, and shrugs off its weight with a remarkable display of agility. In terms of raw point-to-point speed the smooth, sophisticated Mercedes has its hardcore, back-to-basics American cousin well and truly beaten. On a dry track the SRT-10 would probably eat the SL whole, but as a real-world sports car the Viper is fatally flawed.
Which isn't to say it doesn't have its charms. After my first taste of the Viper (evo 075) I thought it was the most disappointing car I'd driven in a very long time: too stiff, too intimidating and impossible to enjoy other than as a car to pose in. But this one seems better. It still hunts and weaves on choppy asphalt but there's none of the suicidal tramlining under braking that blighted that first car, and although it's a real struggle to use those rampant 500 horses, there's genuine fun to be had trying to utilise the available grip and exploit its grunt.
Despite the incredibly unforgiving ride, the Viper points its nose in the air when you unleash the V10, nosedives when you hit the superb brakes and rolls a lot more than you anticipate through corners. You might expect this weight transfer to engender some feel, but it takes a long time before you feel confident to push the SRT-10 hard and you're always limited by its lack of directional stability on rough roads. It's certainly not a subtle and polished device like the SL55, but for all its faults the Viper has a kind of animal magnetism that sucks you in and galvanises you to the challenge of making sense of its edgy and often unpredictable dynamic make-up.
Perhaps the SRT-10's biggest problem is its price. At £77,000 it is impossible to justify. The quality of the materials used for the interior is shocking, the detailing crude, and you get very little in the way of equipment. It's unusual to bring two similarly powerful cars together and at the end of it consider the more expensive car the bargain. The £94,590 SL55 is worth every penny, and maybe a few more. The Viper feels maybe £25K too expensive. A Corvette C6 is more accomplished and more suited to our roads, and although you might pay a premium for the Viper's fury and rarity, to pay an extra £30K or so over the 'Vette is perverse.
Of course the real expense when you buy a Viper is that you need to stump up for an SL55 AMG, too. You'll need a friend with lots of time on his hands to follow you around, and when there's a crowd of excited onlookers swarming for a better view of the SRT-10, just ask him to twist the SL55 into life. They'll leave happy that they've seen the ultimate expression of America's muscle-car culture, and the rich V8 noise will stay with them forever. Now that's product planning. DaimlerChrysler? It's a match made in heaven.
