Boston.com's view

The handling of cars has been described down the years in various ways: handles like a boat; rides like a truck; carves like a ski; cuts like a knife.

It is from the last that I’d like to derive my own description of the 2003 BMW Z4: like driving a switchblade.

Brandish it, switch-button untouched, and its potential for power is subtle yet obvious. After all, its very exterior design is a sculpted flow of knife edges and abrupt blades.

Touch that button, however (it’s labeled sport mode), and the blade snaps out and now you’re ready for some obvious and heavy carving and cutting.

The normal ride is, while stiffer than your standard sedan, still soft enough for comfortable and serene highway cruising. Sport mode, however, is another thing: The suspension gets tighter, harsher; the steering gets heavier and, thus, easier to feel and read; even the throttle reacts differently to sudden jabs at the gas pedal.

There is much on the inside that is different about the Z4 besides this duality of mode. Better engines, better transmissions, better suspensions, lots more room, cleaner interior design.

Yet it is the outside that, prerelease, caused the most controversy.

Last September, in an early preview of the Z4, Road and Track magazine opined, "We’re hoping this is one of those cars that will look better in person than in photographs."

Absolutely, it does. And I see it as a stunning bit of sculpture, a bold use of sharp lines, flowing joints, and crisp edges.

Pull up behind the venerable Z3 (odd that a car only 7 years old can be called venerable) and the Z3 looks downright round and plump. I credit Mazda with bringing back the two-seat roadster (in the ’80s), but I give BMW credit for giving it guts with the Z3 in 1995.

But it did get long in the tooth as both Boxsters from Porsche, for instance, became better cars.

The Z4 is back into the fray with this edgy design and heightened performance. A sharp edge runs from each windshield pillar out to the headlamps. A bulge of the entire hood — not just a power hump as in the Z3 — rises outside the windshield. Yet from inside, those pillar-to-headlamp lines sharply define the front of the car.

A muscular bulge to the rear fenders is noticeable in the outer rearview mirrors. From the outside, a gap that runs down the rear and beneath each door rises up the front quarter panels, disappears into the wheel well, and reappears at the upper edge of the front fender, leading to the headlights.

Sharply scooped sections and bold stampings set this apart from the Z3, yet the twin kidney grille, chopped rear deck, and long hood mark it distinctly BMW.

It is a car that bears a nice resemblance to the Z8, yet reaches back for inspiration to the classic 315/1 and 319/1 of the ’30s and, more spectacularly, to the 507s of the mid- to late-’50s.

It remains weighted 50/50 front-to-rear. Its fron t track, at 59 inches, is 2.4 inches wider than the Z3, while the rear track is 1.2 inches wider at 60.0 inches. The wheel base has been expanded from 96.5 to 98.2 inches and the overall length from 159.4 to 161.1 inches. Retained in the stretching were the trademark minimal overhangs front and rear.

The length and width make for a more spacious cockpit — for both legs and shoulders — and for a far roomier trunk. Helping to preserve that trunk space is the fact that the automatic convertible top (up and down in 10 seconds, heated glass window) comes with an integrated tonneau cover. That means no portable cover has to be stowed in the trunk for top down cruising.

The wider stance and added length only add to the Z4’s sharp blade feel on the road, whether in regular or sport mode. Of course, the sport mode is better honed and the car sits stiff, flat, and controlled even in hard cornering.

Electric steering, using a motor rather than hydraulics, is speed sensi ive, adding more power at slower speeds and while parking, giving the driver more feel as speeds increase.

Dynamic Stability Control uses braking and engine torque applied to each wheel to stop wheel spin and help control understeer, oversteer, and other driver errors. The control can be switched off so that New England drivers can "steer with the gas pedal" as is sometimes necessary in slippery going.

A light suspension using aluminum lower arms and hollow struts up front, and a lightweight multilink system in the rear, keeps unsprung weight down and adds to the feelng of flat, solid stability.

The Z4 comes with two engine options, a 2.5-liter that produces 184 horsepower and a 3.0 (as tested) that rumbles out, in fine tone, 225 horsepower. The latter is electronically limited to 155 miles per hour.

Transmission options are big news with the Z4. The 2.5 comes with a 5-speed manual gearbox while the 3.0 has a nifty, clicking 6-speed manual. Either can be had with a 5-speed Steptronic automatic. And coming for spring, brought to you by the M3, is a Sequential Manual Gearbox with a 6-speed that can be an automatic or a manual, and the latter version can be shifted from paddles on the steering wheel with flicks of the thumb or forefinger.

Safety features for this fast car include rollover protection, dual front and side air bags, and "dedicated" air bags beneath the dash to protect the knees.

Inside, various combinations of leather and cloth, wood and brushed metal, are available. Sport seats are standard. The interior lines — along the dash, the doors, even the armrests — reflect the sharp edges of the exterior. Simple controls highlight a dash panel that seems as stark and efficient as a fine, gleaming, high-tech kitchen.

There will be those who don’t like the Z4’s edginess at first glance, but I urge them to give it a chance. Look particularly for the car in a dark color and walk around it, watching the lines and shadows change, even the color seems to vary by angle of approach. It will grow on you.

Annoyance: That said, I think BMW should have stayed away from silver as a color option. It doesn’t look anywhere as sharp in silver (and there goes at least the glinting threat of my switchblade comparison).

Nice touch: The nifty bin in the rear wall between the bucket seats. Spacious, easily reached, inconspicuous with its hinged door.