BMW M Roadster vs. Chevy Corvette, M-B SLK32 AMG, Porsche Boxster S

BMW M Roadster vs. Chevy Corvette, M-B SLK32 AMG, Porsche Boxster S BMW M Roadster vs. Chevy Corvette, M-B SLK32 AMG, Porsche Boxster S
Comparison Tests

What kind of car did you drive when you were in elementary school? Not your parent's car, your mind's car. Maybe the hardware was branded Schwinn or Huffy or Little Tikes, but admit it: When you took off from a stop, you imagined-maybe even enunciated-the rasp of a cool car running through the gears. If you're in your 50s, maybe you barked the baritone of a straight-six Benz 300SL or Jag XK120. Forty-somethings may have bellowed along to the basso profundo of a Shelby Cobra or Corvette Grand Sport, of the kind occasionally glimpsed racing on Wide World of Sports. After all, for eight-year-old "customers," cost is no object, right?

This author logged lots of neighborhood miles in a racy pedal cart that sounded, rode, and handled-on the internal IMAX-like Get Smart's Sunbeam Tiger, Manix's Hemi 'Cuda, or whatever the latest, hottest, biggest-engined ragtop of the day was (at least the wind in the hair was real). Choosing a car was childishly simple. Coolness and performance were all that mattered. Luggage space, gas mileage, and safety were utterly unimportant.

Today's generation of juvenile car crazies is probably dreaming down the neighborhood sidewalks in one of these four riotous roadsters, and the adults who purchase them for real will likely do so for exactly the same reasons of coolness and fun, with nearly the same disregard for practical considerations. Each represents the state of the art in stuffing big engines into small, nimble-handling chassis that can, in a pinch, be raced. And although each bristles with safety gear, and two offer so much luggage space as to border on practical, the overarching mission of each is quite basic: to generate grins.

Since our most recent test of the cream of this grin-generating roadster crop last August, the third-place-finishing BMW M roadster has been given an all-new engine good for 315 horses, a bump of 75. That test's second-place-finishing Mercedes SLK320 has now been breathed on by AMG, which bolts on a trick new IHI helical-type supercharger and an air-to-water intercooler that harnesses an additional 134 horses to the team, for a total of 349. Each of these quantum upgrades was attended by a commensurate bump in price-$3365 for the Bimmer and an expected $10,000 for the Benz. Porsche boosted the Boxster's power by 33 horses (250 total) with the introduction of the S model last summer, but its $51,484 tariff priced it out of the August test. Not so this time around.

The Chevy Corvette roadster would have squeaked under the price ceiling in the last test, but its perceived deficit in refinement and large size was quoted as reason to exclude it. This year a host of detail changes brings added calm, quiet, and even a bit more horsepower and torque, so it's in. Audi's 225-hp TT Quattro roadster was the newbie last year and therefore has yet to be upgraded, so its lowish $39,508 base price excused it from this bucks-up redo.

Our contestants hail from as far apart as Stuttgart, Germany; Bowling Green, Kentucky; and Spartanburg, South Carolina. They also make their power in completely different ways. The Vette relies on old-fashioned pushrod V-8 displacement-5.7 liters' worth-and BMW uses high tech to make its straight-six sing. Mercedes routes its supercharged V-6 power through the group's only automatic transmission, which boasts AMG shift logic. The mid-engined Porsche gets some 911 parts bolted to its bored-out 3.2-liter flat-six. Yet despite the differences in approach, a wide-open run to 60 mph takes exactly 4.5 seconds in three of the four, with the Boxster lagging just 0.8 second behind.

Clearly, there's some consensus among the manufacturers as to what kind of shove in the backside it takes to make adult drivers smile. But of course there's more to it than hitting the gas and hanging on. So we set off for some roller-coastering in and around Athens, Ohio, in search of our respective inner children. We grinned. A lot.