The Z4 was launched on the world in late 2002, arriving in the UK market in Spring 2003. The line-up was simple: either the 231 bhp 3-litre six or the same engine in 192 bhp, 2.5-litre form. Thanks to the Z4’s relatively light weight (it’s 30 kg lighter than the Z3), both were pretty quick cars and the 3-litre had the measure of the Boxster with 0-60 mph in 5.9 seconds. In 2004 the range was broadened with a new ‘entry level’ 170 bhp version using the smooth-revving 2.2-litre six as found in the 320i and 520i. Standard transmission was a conventional manual box (five speeder on 2.5i and six-speed on 3.0i) or Steptronic automatic, while the 2.5i and 3.0i were optionally available with the sequential manual SMG gearbox. A four-cylinder, 150 bhp 2.0i model was announced in January 2005, going on sale in May.

Production of the much-rumoured Z4 coupe was confirmed by BMW in December 2005 and a revised Z4 range was announced in February 2006. Alongside a new engine lineup, styling tweaks included restyled front and rear bumpers, redesigned headlights, restyled side repeaters and revised tail lights. The Sport spec was also offered for the first time, bringing with it 18 inch alloys, sports seats, alloy dash trim, M three-spoke steering wheel
and M Sports suspension. Engines were now the entry-level 2.0 Valvetronic four-cylinder, the 2.5-litre six in either 177 bhp or 218 bhp in the new ‘si’ model, plus a revised 3-litre six now cranking out 265 bhp and badged ‘3.0si’. At the same time of course, the Z4 received the 343 bhp M3 motor and became the new M Roadster/ Coupe, but that’s a whole different ball game and the subject of a future buying guide in its own right.

The facelift did away with the SMG gearbox, too: a six-speed manual is standard with automatic optional on the six-cylinder models, the SMG brigade kept (almost) happy with steering wheel shift paddles on ‘si’ models. Today, there’s a keen Z3 v Z4 debate and talking to the BMW Car Club’s Z Register reveals that surprisingly few people made the swap from one to the other. Does that make BMW right or wrong..?