2006 M Roadster

Offering more for less is a powerful selling tool. BMW hopes that approach will persuade prospective buyers of topless Teutonic tin to opt for its all-new BMW M Roadster instead of, say, that other roadster from Stuttgart. You know the one, the dream machine we said had "superb mid-engine balance, high cornering limits, scythelike steering," and a "wailing flat-six." But after a preview drive through southern Spain and a track session at the Circuito de Jerez in BMW's second-generation M Roadster, which packs 50 horsepower more than a Porsche Boxster S yet stickers for $3500 less, we can confidently tell you Porsche has legitimate cause for concern.

Like its predecessor, essentially a steroidal BMW Z3, the new BMW M Roadster is a high-protein version of the brand's Z convertible, in this case the face-lifted Z4--which, for 2006, receives freshened fascias and BMW's magnesium/aluminum N52 3.0-liter engine. Stylistically, the jump from Z to M is modest, but a roundel eye will spot the differences: two longitudinal humps in the aluminum hood; a sportier nose with larger air intakes; 18-inch double-spoke wheels wearing 225/45s in front and 255/40s in back; a more aggressive rear end with four chrome exhaust tips and a black diffuser; and, of course, the necessary M badges on the front three-quarter panels and the rear decklid. BMW prefers its M cars to appear "subtle and purposeful," and the roadster successfully conveys the credo.

That philosophy carries over inside, where the BMW M Roadster gets understated tweaks to jazz up the cockpit. The leather-wrapped steering wheel, adorned with the usual red-and-blue stitching, is thicker-rimmed than Buddy Holly's eyeglasses but looks appropriate and, more important, feels just right in the hands. Standard M sport seats, featuring embossed M logos on the head restraints, provide support in all the right places and wear soft leather upholstery, which also ornaments the door panels, handbrake, and shifter. The M's dominant dash decoration--a thick trim piece that sweeps from A-pillar to A-pillar--comes standard with a new brushed-aluminum surface, but also can be had dressed in carbon-fiber-look leather (a no-cost option) or walnut wood. Of course, the interior bit that really adds spice is the 9000-rpm tachometer scale, which, as in the BMW M3, sports a variable warning segment that adjusts the redline according to engine temp. This is useful because, once the 8000-rpm light turns off, the concert can begin.

Borrowed from the BMW M3, yet putting out three less horsepower due to more constrictive space for the exhaust, the BMW M Roadster's S54 inline-six mill not only produces 330 horsepower at 7900 rpm, but also plays mechanical notes so pleasing you'll want to put the sweet song of successive redline shifts on repeat mode. It's an engine that zings as much as it sings; and in a car that weighs over 200 pounds less than an BMW M3 coupe, its three-horse deficit means as much as a politician's promise. BMW claims the M Roadster can accelerate from 0 to 60 in 4.9 seconds, but the company is notoriously conservative with its figures. A 3383-pound M3 Competition Package we tested needed just 4.8, so the roadster is likely capable of around 4.7, or 0.3 quicker than a Boxster S. Top speed is limited to 155 mph.