2008 BMW 6-Series

BMW finally gives its voluptuous 6-Series coupe its hot rod "M" treatment with a 500-horsepower V10 for 2006. The regular 6-Series coupe and convertible also get more power, but all have an awkwardly styled rear end that looks like it belongs on another car.

The 2007 6-Series versions are virtually carryovers, although the convertible gets the M6 coupe's 5.0-liter V10 later this year, along with its 7-speed Sequential Manual Gearbox (SMG). The "M" trim levels come from BMW's hot rod subsidiary.

All 6-Series cars are big, heavy, rear-wheel-drive autos that weigh about 4,000 pounds, but are very fast and have athletic moves. The back seat, though, is best suited to children.

The bulky rear end of the 6-Series was widely criticized when the 6-Series arrived several years ago, partly because BMW coupes had been beautifully styled, from front to back. At least the 6-Series styling up to the back end is sleek, and the oddly shaped rear with its pronounced trunk lid allows more cargo room.

The conventional 2006 6-Series $71,800 650Ci coupe and $78,800 650Ci soft-top got a 4.8-liter 360-horsepower V8 to replace a 325-horsepower V8. They're offered with a 6-speed manual gearbox or 6-speed automatic transmission. Again, no changes for 2007.

Unusual Convertible Top
The convertible's power soft-top has an unusual heated glass rear window that lowers for roof-up ventilation and raises to deflect top-down cockpit drafts.

Every 6-Series trim level has anti-lock brakes, traction/skid control system and BMW's active roll stabilization system to fight excessive body lean. A Dynamic Drive Control adjusts the suspension, throttle and transmission shift points for sporty driving. A special steering system standard on the M6 and optional on the other trim levels quickens steering reaction at lower speeds.

Front torso side airbags and front knee airbags are standard, and the coupe adds head-protecting side airbags.

Also standard are a navigation system, handy steering-linked headlights and BMW's controversial iDrive system that uses a front console control to adjust major climate, audio and navigation functions, but causes a driver to remove complete attention from the road.

Most Spectacular Version
I recently tested the most spectacular 6-Series version—the $96,100 M6. This trim level comes with a $3,000 gas guzzler tax. That tax, along with some options and a destination charge, raised my test car's price to $106,390.

The M6 does 0-60 mph in a sizzling 4.1 seconds and tops out at an electronically limited 155 mph for the American market. Otherwise, it would probably easily reach 175 mph or more.

Every person who buys or leases a new M6 will be its guest for a course in advanced driving techniques in M6s at BMW's Performance Center in South Carolina. I took an intensive "M" course there a few years ago in various BMW M models and recommend that M6 drivers do the same.

Premium gasoline is required for the M6's ultrasophisticated 40-valve engine, which has variable valve timing.

Two Horsepower Settings
Pushing a console button that reads "Power" raises horsepower from 400 for routine driving to 500 and provides quicker throttle response for more aggressive motoring. A "P500 Sport" setting allows full engine power, but provides even quicker throttle response; it's selectable only in the MDrive menu on iDrive.

Fuel economy is an M6 weak point. It's an estimated 12 mpg in the city and 18 on highways. The 650Ci convertible and coupe do better, delivering 15 city and 23 highway with the manual gearbox and 17 and 25 with the automatic transmission.

Frightfully Complex
All 6-Series trim levels are complex, but the M6 is frightfully complex. It has the usual long list of luxury auto comfort and convenience features and safety items found in all 6-Series trim levels and electronic adjustments for everything from the suspension and steering to its Sequential Manual Gearbox. That gearbox can be put into six manual shift programs and five automated programs.

The M6 has special steering, sports suspension , huge 19-inch tires and stronger brakes.

A carbon fiber roof enables the M6 to be several inches lower than BMW's M5 sedan to reduce weight and lower the center of gravity to enhance handling.

Also making the M6 safer during hard driving is the Dynamic Stability Control (DSC) system. It includes (take a deep breath) all-speed traction control, electronic brake proportioning, anti-lock braking, cornering/braking stability enhancement, Dynamic Brake Control, Brake Standby, Brake Drying, Start-off "Assistant"—besides M Dynamic mode and M Variable Differential Lock.

Explaining most of those features would put anyone but an auto engineer to sleep.

Long doors with large outside handles allow easy entry, at least when the M6 isn't in tight parking spots.

Fairly Large Trunk
My test M6's thick owner's manual was in the trunk because there was no room for it in the rather snug, but not cramped, interior. However, the fairly large trunk provides decent cargo room.

The wood-and-leather interior is luxurious, with supportive front seats, easily gripped steering wheel and gauges that can be quickly read.

The Sequential Manual Gearbox can be shifted manually with two steering-wheel-mounted paddles (one for upshifts, the other for downshifts). This gearbox also can be put in fully automatic mode, but that results in often slow, rather jerky gear changes.

No Park Mode
First time M6 drives who only know about the SMG's automatic mode might be alarmed to learn after parking that the transmission can't be moved into a "park" position—only into a "neutral" position because it's not a fully automatic transmission. You thus must leave the M6 in "neutral" and use the parking brake to prevent the car from, say, rolling backward when on an incline.

Manually shifting the gearbox while briefly taking my foot off the accelerator between shifts allowed smoother gear changes than leaving it in automatic mode. But I soon tired of using the paddle shifters in routine driving and just left the transmission in automatic mode. A conventional 6-speed manual transmission may be offered next year for the M6.

An M6 owner can never safely use its full potential unless he lives in the middle of nowhere and has considerable driving expertise. Most are best off with the regular 6-Series trim levels, although I certainly wouldn't kick an M6 out of my garage.