Sometime between the E30 M3 of the 1980s and now, the market for M-badged BMWs expanded to execs in blue pin-striped shirts and Ray Ban aviators. Maybe more aspiring one-percenters became auto enthusiasts, but the company also just cast the net wider; older models like the E34 M5 weeded out the boulevard poseurs by only offering a manual transmission. Compare that to the last-generation M5, which initially only came with an (SMG) automatic — and outsold all preceding M5s. Do the 2013 BMW M5 and 2013 BMW M6 continue that same mass-market trajectory? To answer that question, BMW gave us the opportunity to drive them at Mazda Raceway Laguna Seca and on the streets of Monterey, Calif.
At first glance it may seem odd to compare the M5 and M6 because of the stark difference in sheet metal, but underneath they're closely related; both are powered by a turbo V-8 making 560 hp, have a rear axle rigidly mounted to the unibody, and use hydraulic steering for better steering feel.
Dynamically the two are similar, but on the track the M6 is more athletic and agile, and tackles the bends with a sharper, flatter poise—aided by the carbon-fiber roof panel, which sheds over 10 pounds up top. The carbon ceramic brakes (a hefty $8,700 option) also give a better bite than the standard M5 steel discs. Both cars barrel through the bends with a well-composed neutrality—but gas out of the corner too eagerly and the 500 ft-lbs of torque will make the rear tires shriek in agony as the tail swings out. Fortunately, the M Dynamic Mode (MDM) empowers drivers to control the car at 9/10ths of the limit without fear of plowing into tire barriers, and the system adroitly intervenes as the rear starts to wiggle. But technical wizardry aside, there's no escaping the Newtonian reality that M5 and M6 are heavy — each weighing over 4,200lbs — and you feel it especially in the M5.
With more weight comes more power, and while some may bemoan the shift from the naturally aspirated V-10 to a turbo 4.4-liter V-8, it's a near-flawless engine, with a generous torque band that effortlessly handles the elevation changes at the famed track. The only shortcoming is that BMW pumps artificial engine sounds through the speakers. A phony engine soundtrack should never be a touted feature; whether behind the wheel or in the bedroom, knowing the noises are faked only lessens the experience.
Unlike the previous generation's clunky SMG, the impeccable automatic transmission on the 2013 M5 and M6 not only shift faster than you can blink, but is also almost undiscernibly smooth when cruising. Ironically, it's so good that I preferred it to the six-speed manual (only available with the M5), which although is competent on the track, has a clutch that's too grabby for street driving. Also, downshifts that rev-match feel wrong; if I'm choosing manual for the sensation of control, I don't want a computer to do the leg work for me.
Although the M6 has a performance edge over the M5, the latter shined on regular roads — it shrugged off the choppy roads of Highway 68 with a relaxed yet confident ride. On the other hand, the crisp dynamics of the BMW M6 became an annoyance when leaving the smooth track. Traversing the same stretch of highway as the F10 M5, the patchy asphalt quickly became tiresome even in Comfort Plus mode.
Both M cars are undeniably driver's cars, but I couldn't grasp the point of the M6; the two-ton weight of the 6 Series is understandable because grand tourers are supposed to be supple land yachts. And I can look past the added heft of the M5 because it's a daily drivable saloon, and doesn't have the same racing history as the M6 (whose ancestor was the classic 3.0 CS). But if I wanted a trackable GT the exemplary BMW M3 is cheaper, more nimble and light, and has near-telepathic steering feel. With a starting price of $106,100, the M6 is neither supercar-fast like the cheaper Nissan GT-R, nor as elegantly executed as the Jaguar XKR.
So while the 2013 M5 is everything an M5 should be — a paradoxically posh luxury sedan that feels at home on the track — the finely engineered but flawed M6 needs a crash diet to fit in its pinstripes.
2013 BMW M5
Midsize luxury sports sedan
7-speed DCT automatic or 6-speed manual
4,343 lbs (manual); 4,387 (DCT)
4.3 (manual); 4.2 (DCT)
8.6 tons CO2/year
15/22 mpg (manual); 14/20 (DCT)
Gained weight over the years
Still has the M5 allure
2013 BMW M6
High-performance grand tourer
7-speed DCT automatic
4255 lbs (Coupe); 4508 (Convertible)
4.1 (Coupe); 4.2 (Convertible)
8.6 tons CO2/year
Suspension too choppy for daily use
Powerful V-8 with a wide torque band