TRADITIONALLY, BMW makes some of the smoothest straight-sixes in the world.

So, when BMW announced its latest roadster would debut with either a 2.5-liter or 3.0-liter version, nixing the inline-four strategy of the first Z3, we knew history was on the Z4’s side.

The 3.0-liter inline-six powering the Z4 is a torque-rich, easy-revving stalwart put to use across BMW’s U.S. line, save Z8 and 7 Series. This particular application knocks out 225 hp and 214 lb-ft, launching the car from 0 to 60 mph in 5.88 seconds, just 0.14 second off the 250-hp Porsche Boxster S (AW, Oct. 23, 2000) and 0.17 second faster than the 2.8-liter Z3. The quarter-mile was neck-and-neck, with the Z4 checking in at 98.3 mph in 14.38 seconds, a quarter-second faster than its predecessor; the Boxster S went a bit faster at 97.6 mph in 14.26 seconds. The Honda S2000 and Nissan 350Z also bettered the Z4.

The Boxster/Z4 debate will rage on, but Boxster-beater or not, “After [test driving] the Z3, the Z4 feels like the car BMW needed to build,” said one owner, whose two-year roadster shopping trip ended two months ago at a BMW dealership. His point: BMW earned his money because it built a Z3-beater.

As for acceleration, throttle response was, at first, a bit slow, possibly attributable to a heavy flywheel and/or electronic throttle programming. Sitting stationary with clutch down, our tester quickly floor- ed the pedal but couldn’t motivate the tach past 1500 rpm by the time full throttle was achieved.

The throttle lag did not persist and launching became silk at 2000 rpm or lower— at 2500, wheels spin all the way to redline. We turned off traction and stability control for testing.

Our 20-to-40-mph and 40-to-60-mph times were both achieved in second gear covering 2000 to 4000 rpm and 4000 to 6000 rpm respectively, suggesting strong pull regardless of engine speed, thanks in part to BMW’s variable valve timing. The Z4 edged out the Boxster S, S2000 and 350Z with a 46.4-mph slalom, but fell behind the 0.90 g posted by the Boxster S and S2000 on the skidpad.

The Z4 shone under braking. The S2000 ate up 207 feet of road before reaching a dead stop from 80 mph and 116 feet of road from 60 mph. The Boxster S and 350Z needed 198 and 205 feet respectively to stop from 80 mph; 111 and 114 feet from 60 mph. The Z4’s numbers spanked ’em all from 80 mph, at 189 feet to stop, and the car squeaked past the Boxster S from 60 mph, at 110 feet. Its 27-foot stop from 30 mph also topped the lot. Much of that performance comes from the Bridgestone Potenzas fitting the 18-inch wheels.

Unlike braking, design proficiency isn’t quantified by a yardstick. One owner described the design as “hard to grasp.” A reader told us that, thanks to the droopy headlights, the Z4 looks as if it’s about to cry when gazed upon via the rearview mirror. In all, 75 percent of owners question-ed the styling at first, but with familiarity came affection.

The interior is appropriately Teutonic, cold yet accommodating. While some owners complimented Bimmer interior planners for providing plenty of stashing portals and room aft for golf bags, we were impressed with racer touches such as knee padding wrapped around the transmission tunnel. Thanks to steering wheel adjusters and well-bolstered, eight-way power seats, we could easily find the perfect driving position.

As for the price tag, not everyone can afford a Z4, but some of those who could—whether picking the 3.0-liter or 2.5-liter version—let their pocketbooks make the decision between BMW and Porsche. Our test car came well stack- ed, optioned up nearly $4,000 thanks to a premium package, a/c and a specialty paint job.

Then again, the Z4’s price is still at least 7K slimmer than a Boxster S, but we’re not talking about a Boxster S, not now anyway. Let the debate continue.

OWNERS SAY...

Once I drove the Z4 for a day my mind was made up, and I bought it. It’s fast, roomy, solid and stable, and it hustles on call. It also feels much better as a daily driver than the other cars that I drove. The steering is light at times, but press the sport button and it sharpens that up along with quicker throttle response and shift points. The styling grows on me every day, and I’ve never had so much positive reaction from so many people. George Chalfant, Ukiah, Calif.

I briefly considered the Porsche Boxster, but when similarly equipped as the Z4, the price difference was too great. I love everything except the cupholders and the tiny glove compartment. I had the M Roadster, and this car is significantly better in all areas. Did I mention how much I miss the plastic rear window and convertible boot of the Z3? No, that’s because I don’t. Tom Deimling, Beaverton, Ore.

I wasn’t wild about the styling, but it has grown on me. But some colors look better than others. I pondered buying it for more than a month. It was between a Porsche Boxster and Z4, but I chose the BMW. The interior is gorgeous, and it was hard to overlook the $10,000 savings and four-year/50,000-mile no-charge maintenance. It’s great fun to drive while still including all the luxury toys I’m used to in my 530i. Roger Triplett, Birmingham, Mich.

What I love about the Z4 is the handling and feel of connection to the road. I considered the Boxster, but the deals were too good to pass up the Z4. I can also fit two sets of golf clubs in the trunk, and the interior is top-notch. I also like the interior layout very much. While storage space is at a premium in this type of car, BMW did add several extra stashes. Believe me, the styling looks much better in person than it does in photos. Larry Engelberg, Dix Hills, N.Y.

Specs and Data

MANUFACTURER INFO
BMW of North America
300 Chestnut Ridge Road
Woodcliff Lake NJ 07677
Customer assistance: (800) 831-1117
Internet address: www.bmwusa.com
Country of origin: United States
Number of dealers: 340

STICKER
Base: $40,945
As tested
(includes $695 delivery): $44,820
Owners paid; average: $38,040 to $47,800; $42,360

OPTIONS AS TESTED
Premium package, which includes auto-
matic power soft-top and power seats with
driver memory ($1,500); air conditioning
($700); bixenon headlights ($700); heated
seats ($500); metallic paint ($475)

OTHER MAJOR OPTIONS
Navigation system ($1,700); sequential
manual gearbox ($1,500); five-speed
automatic ($1,275); sport package, which
includes 18-inch wheels and tires, sport
suspension and dynamic driving control
($1,200); convenience package, which
includes automatic climate control, auto-
dimming mirrors, storage compartments
and rain-sensing wipers ($850); wood trim
($200); graphite trim ($150)

CHASSIS
Unibody, two-door convertible

DIMENSIONS
Wheelbase (in): 98.2
Track (in): 58.0 front,
60.0 rear
Length/width/height (in): 161.1/70.1/50.1
Curb weight/GVWR (lbs): 2998/3549

CAPACITIES
Fuel (gal): 14.5
Cargo (cu ft): 8.5

ENGINE
Front-longitudinal 3.0-liter/182-cid dohc I6
Horsepower: 225 @ 5900 rpm
Torque (lb-ft): 214 @ 3500 rpm
Compression ratio: 10.2:1
Fuel requirement: 91 octane

DRIVETRAIN
Rear-wheel drive
Transmission: Six-speed manual
Final drive ratio: 3.07:1

SUSPENSION
Front: Struts with coil springs, gas-charged
shocks, antiroll bar
Rear: Multilink with coil springs, gas-charged
shocks, antiroll bar

BRAKES/WHEELS/TIRES
Discs front and rear, ABS
Aluminum 225/40R-18 front, 255/35R-18 rear
Bridgestone Potenza RE050 run-flats

STANDING-START ACCELERATION
0-60 mph: 5.88 sec
0-100 km/h (62.1 mph): 6.42 sec
0-quarter-mile: 14.38 sec @
98.3 mph

ROLLING ACCELERATION
20-40 mph (second gear): 2.5 sec
40-60 mph (second gear): 2.7 sec
60-80 mph (third gear): 4.0 sec

BRAKING
60 mph-0: 110 ft

HANDLING
490-foot slalom: 46.4 mph
Lateral acceleration
(200-foot skidpad): 0.89 g

INTERIOR NOISE (dBA)
Idle: 45
Full throttle: 86
Steady 60 mph: 67

FUEL MILEAGE
EPA combined: 24.04 mpg
AW overall: 20.56 mpg

RESIDUALS
$28,812 after 60-month lease,
64 percent of new vehicle price