BMW Z4 3.0 Si Coupé Sport review
by David Finlay (21 August 2006)
It all comes down to what you want a car to do for you. If you're looking for something with bags of potential (which you might not necessarily ever use) and enough in-your-face styling cues to show that you have deep enough pockets to spend more than the next guy, the car to go for in the BMW Z4 Coupé range is undoubtedly the M model. If you want something that's good to drive, forget the M and go for the 3.0 Si instead.
This may seem like a paradox. Surely the M is the real driver's car? It has nearly 80bhp more than the Si, with brakes and suspension to match, and prototypes were pounded round the Nürburgring for days on end to achieve the desired set-up. BMW's M Sport Division even abandoned run-flat tyres and opted for conventional hydraulic power steering (rather than the Si's more modern electronic assistance) to maximise the driving experience. Even so, the Si is the better car.
Or at least it's better in virtually all the circumstances a UK driver will use it for. Oh, the M will be much quicker round the Nürburgring, and probably round every race circuit in the UK too. And if your idea of performance driving is to bury the throttle pedal in the carpet and leave it there, the M will leave the Si trailing.
So why is the Si better? Well, for a start, it is very much easier to drive (and I don't buy the idea that high-performance road cars are better the more awkward and recalcitrant they are - that usually just means they haven't been properly set-up). The Si has less power and torque than the M, so it doesn't need such a heavy clutch, and gearchanges are correspondingly easier.
BMW has fitted the Si with a narrower-rimmed steering wheel than you'll find on the M, and it's much more comfortable to use. You drive the Si with your fingertips, while the M almost obliges you to drive it with your fists. And although the M's highly-tuned suspension works well on beautifully smooth roads, in the real world the Si is considerably more forgiving, as if it will help you round corners rather than huffily leaping into the scenery if you don't come up to its expectations.
The performance issue isn't that clear-cut either. Of course the M is ultimately quicker, but the lightweight aluminium six-cylinder engine in the Si is still pretty strong, with a maximum output of 265bhp. Up to about 3000rpm its power curve matches that of the M, and how often do most of us exceed 3000rpm by much in normal driving?
BMW estimates that 80% of Z4 Coupé customers will opt for the 3.0 Si Sport tested here. There is a lower-spec SE version, but experience in other model ranges suggests that Sport will be much more popular (95% of all X5s sold in this country are Sports, for example).
The £1525 upgrade from SE to Sport involves just the sort of equipment that BMW customers like to have. 18" wheels, for a start (in composite alloy as an option), plus Dakota leather upholstery, anthracite headlining, and three-spoke leather steering wheel and M Sports suspension. I haven't yet driven an SE, but perhaps its more compliant suspension makes it even more pleasant on the road, though I doubt that many customers will trade that in for the lack of leather and the smaller wheels.
Whatever the model, the Z4 is reasonably practical for a sports car, with 340 litres of boot space (285 litres of which can be hidden under a retractable load cover) plus one 10-litre storage box in the rear bulkhead and two 3.7-litre compartments, one each side of the interior.
Standard safety equipment includes BMW's Dynamic Stability Control+ system, which includes automatic stability control, corner brake control, EBD, brake pre-tensioning, brake drying, brake fade compensation, hill start assist and something called Soft Stop, which reduces the braking force as you come to a halt. Satellite navigation and Bluetooth phone preparation are also included in the price.