Building a hardtop version of a roadster seems counterintuitive, as people like convertibles, but BMW consistently places engineering over popularity. With the 2007 BMW Z4 M Coupe, BMW relies on people to appreciate the performance of the car rather than whether you can get a suntan in it. And the M Coupe performs fantastically, with an engine that sounds angry when the rpms get significant.
But this isn't a stripped-down speed machine--the M Coupe gets a full raft of cabin tech to make the car a helpful partner in everyday driving. Our test car shipped with a pop-up navigation screen, Bluetooth cell phone integration, and a thumping stereo system that handles MP3 CDs.
The M Coupe gave us an adrenaline-filled week, but it's not without drawbacks. The rudimentary interface for the cabin gadgets makes it seem like the engineers, in a fit of pique over all the bad press about iDrive, only put about five minutes of work into it. And you can have much more fun with the M Coupe by turning off the overly aggressive traction control, which doesn't let you get away with anything. The suspension also felt a little rubbery where we expected a rigid sports car feel.
Test the tech: Old versus new
BMW produced a coupe version of its old Z3 roadster in limited numbers from 1999 to 2002, the inspiration for the new coupe based on the Z4. As one of our staff editors owns a 1999 Z3 Coupe, we compared the old and the new, driving them over the same twisty mountain roads and taking stock of their available equipment. Unfortunately, the 1999 Z3 Coupe is not the M version, so our M Coupe test car is much more powerful.
Z3 Coupes were better equipped than the Z3 roadsters as standard, complete with a nine speaker Harman-Kardon stereo system. The stereo was a single-CD player in the dash, with an optional six-disc changer mounted in the cargo area. The Z3 Coupe had a tweeter and mid in each door, plus a tweeter and mid mounted to the ceiling over the cargo area, one set on both sides. There was also a subwoofer mounted in the cargo area.

The Z4 M Coupe has the same arrangement in the doors, plus speakers mounted behind the seats and a subwoofer in its cargo area. The audio quality in the newer car is stronger, with heavier bass, but the older car has better clarity. The Z4 M Coupe has a single-CD player, too, but it handles MP3 CDs, and also has an auxiliary audio input. But then the newer car blows away the older one by also offering a navigation system and Bluetooth cell phone integration, beating it out on the cabin gadgets.
Both cars handle exceptionally well, but the steering wheel on the Z4 M Coupe is smaller and thicker, with more oversteer. We took both cars on our three favorite local roads: Tunitas Creek and Alpine in the Santa Cruz mountains, and Fairfax-Bolinas Road in Marin. We quickly found that the more modern and aggressive traction control on the Z4 M Coupe kept the rear from stepping out at all, whereas the older car could practically turn on a dime on hairpins by pushing its back tires out. When we turned off traction control in the Z4 M Coupe, we got much the same effect.
Our old Z3 Coupe uses a 2.8-liter straight six, while the new Z4 M Coupe has a 3.2-liter straight six with BMW's Double-VANOS system of variable valve timing. The slightly bigger engine produces about 140 more horsepower, a huge gain. The newer car also gets six gears over the Z3's five, but both manual transmissions had a similar shift feel. On our twisty roads, though, only second and third count. In second at 5,000rpm, the Z4 M Coupe's engine makes a very angry noise, while the Z3 Coupe has a more tenable sound.

Finally, the suspension feel of the Z4 M Coupe had a rubbery feel, where the Z3 Coupe's was sports car rigid. There is also more available cargo area in the Z3 Coupe than in the Z4 M Coupe. Some people will also prefer the more outlandish style of the older car. As a tech car, the Z4 M Coupe far outstrips the Z3 Coupe, bringing technology not generally available in cars from 1999. And the newer car will knock the older out on the straighter roads, but they run close together on the twisties.
In the cabin
The cabin of the M Coupe is appropriately tight for a two-seat sports car, but the seats have a good range of power adjustment, including vertical. The three spoke steering wheel has a thick rim, making it easy to grip. Buttons for the stereo, telephone, and voice command are mounted on the lateral spokes. The voice command system controls only the hands-free phone system, although we had significant trouble getting it to recognize our commands.
For the navigation option, BMW mounts an LCD in the dashboard that pops up when in use. This position permits a lot of glare on sunny days, making the screen difficult to read, especially through sunglasses. When you hit the menu button, the screen shows an interface that looks unfinished. It gives you options for navigation, telephone, trip information, audio settings, and system settings. This screen could use a graphic treatment. And, strangely, you can't access the stereo from this interface.

Instead of iDrive, which we last saw on the BMW 535, this system uses a menu button and combination knob-push-button. These buttons, combined with the onscreen interface, were not at all intuitive to use. But during our week with the car we managed to figure out how everything worked and grew to appreciate its simplicity. The system needs some serious refinement and better feedback onscreen.