Unlike regular 6ers, the M6 is equipped with hydraulic assist for the power steering. You may already know that the M6’s close sibling, the M5 sedan, has hydraulic steering, too. Both cars also share a 560-hp, 4.4-liter twin-turbo V-8 that employs the M division’s trick manifold that evenly spaces out exhaust pulses. Both convert engine rpm to tire rotation through a seven-speed dual-clutch automatic. (We’ve been promised a six-speed manual for the U.S.-market M5; fitting that transmission to the M6 is “possible,” we’re told, but not confirmed.) Both have launch-control programs, fuel-saving engine stop-start systems, adjustable throttle and damper settings, and so on. One key area in which the two differ—vastly—is steering feel. The M6 has it, the M5 largely doesn’t. Another puzzle.
The head-scratching continues when you consider the M6’s brakes and suspension. In an upcoming comparison test, you’ll read about the M5’s weak brake bite and its ride quality, which suffers from excessive up and down motion. Perhaps the difference can be chalked up to the German roads we traversed in the M5 versus the South Carolinian byways outside of BMW’s Spartanburg assembly plant (which also acts as a port of entry for German-built models such as the M6). Or maybe the fact that the M6 was driven solo, without comparison-test rivals to chisel out its faults. Whatever the case, the M6 convertible’s brakes are sharp and its ride motions restrained.
As with the rest of the new-gen 6-series lineup, the manatee-like lumpiness of the previous car has given way to muscular creasing and a sleeker profile. This cloth-roofed droptop is still heavy—4509 pounds, or 232 more than a Euro-spec M5—in part explaining a quarter-mile sprint 0.5 second behind the quickest we’ve recorded for the M5, but 12.4 seconds is still plenty quick. The M6 droptop achieves 60 mph from rest in 4.0 seconds.
There is little to confuse in the M6’s dynamics, though; it drives the way it does because it’s big and powerful. Get too aggressive with the front end and the nose will attempt to plow. Goose the accelerator too hard and you’ll see either the stability-control light or tire smoke, possibly both. The M6’s heft and 192.8-inch length make it more of a grand tourer and less of a sports car, although this latest version manages transitions with much more grace than did its predecessor. It’s easy to achieve high speeds and to reach the 0.92-g skidpad limit, but the M6 doesn’t pretend to be as razor-sharp as the M3. Another nod toward this car’s GT nature is its engine note, which is softer than we’d like, especially in a convertible. And there is no tantalizing off-throttle burble.
The M6 convertible improves on its predecessor in every way, save sonic quality—the previous car’s wailing, naturally aspirated V-10 is a hard act to follow—which is easy to understand given that the old car debuted for 2006. But how did the M6 end up trumping its M5 cognate in such critical areas? We’re stumped, and we haven’t even driven the 2013 M6 coupe yet.
