BMW Z4 2010 review

The new roadster has plenty of M stuff, and the performance to match a manual M3 coupe, but BMW Australia says it's not a true M car and not entitled to the badge which brings ultimate BMW bragging rights. Instead, in the confusing BMW world of 2010, the rapid twin-turbo Roadster is called the sDrive35is.

To translate into the stuff that matters, it has a force-fed six that makes 250kW/500Nm, a seven-speed double-clutch sports auto gearbox, adaptive M suspension, 18-inch alloys and a unique bark from its twin- pipe exhaust.

The car is priced from $129,900 and aimed straight at the Porsche Boxster, although BMW Australia concedes there could be some people who will shop it against an Audi TTRS, something AMG from Benz, or even a Nissan 370Z.

The change away from a true M-car in the Z4 range shows the work pressure on BMW's hot shop, which has only just finished the X5 and X6 and is now deeply into the next V8 turbo M5, as well as a slight direction change for the two-seater convertible. It's not as extreme these days.

Value

The price hardly matters because BMW Australia only has 25 cars for the rest of the year and is expecting a similar tight supply through 2011. But it's $129,900 without an - inevitable - extra dip through the optional-equipment list.

That puts it straight up against the Boxster, which starts at $105,000 these days, and it even undercuts the Boxster S which is the real choice for keen drivers. Then again, there will be an all-new Boxster next year which promises a lot more - including space - than today's car.

"It's the Boxster that we're really got in our sights. It raises the perfomrance to the standard of the Porsche," says Piers Scott, spokesman for BMW Australia. He touts the changes and particularly the unique-design alloy wheels, M logos on things like the steering wheel and scuff plates inside the wheel, as well as the lower ride height and the unique exhaust note.

But he also concedes the Z4, across the board, is not a big seller in Australia. This year's running sales total is 188 against 126 in 2009, despite the arrival of an all-new model. "They are not flying out the door. Globally it has been a huge success story and leads the segment by far, but in Australia it is still to find its feet," he admits.

Technology

The key to the car is the twin-turbo six, which uses one turbocharger each for three cylinders, to deliver peak torque from just 1500 revs and overboost of 500 Newton-metres under high-load conditions. Peak power comes at 5900 revs, relatively low against M cars with redlines around 8000.

The double-clutch gearbox is the right choice for the car, although it still has the silly auto-style shift levers of the cruisey BMWs, and the adaptive suspension is set lower with the ability for more firmness and grip. The driver assist systems are also switchable to ensure maximum fun.

"For the pure enthusiast, it's a performance car that's track capable," says Scott.

As for the exhaust note, it's not a pure M system but has been tuned to give a better note.

Design

The latest Z4 is slightly bigger and slightly more rounded, with more cabin space than before. It still has a folding hardtop that works quickly and easily, with a cabin that has the right stuff in the right places.

The changes for the M upgrade are minor, but enough for BMW enthusiasts to know the difference.

Driving

The second-generation Z4 came with more poise and balance than the previous car, which makes it better for an M-style upgrade. It copes easily with the extra power and torque, instead of turning into a bucking broncho, and never feels to be stretched beyond its limits. The nose will push wide if you get onto the power too hard or too early in a tight bend, but generally it just tracks around a curve and invites you to dip into the loud pedal.

When you do there is a very sweet thump from the exhaust, although it's not the same as the howl from a non-turbo six or V8 from the M-car menu.

It is an extremely rapid car at all times on all types of roads, but is not lairy or overdone. In fact, it's remarkably refined and that should work for people who are considering a Boxster. The gearbox is terrific for maintaining swift motoring, although the engine will drop below ideal boost in tight corners as second is a bit too tall. It recovers boost quickly, but is something you notice. The ride is firm but not shaky, the seats are great, there is good feel to the suspension and the brakes never feel troubled, even at fairly rapid speed.

The Z4 hero is a true hero and definitely capable of challenging the Porsche Boxster, but you have to wonder if people with the right money would also want the right badge - an M - to tell people what they have in the garage.