Here's a little info:
What's good: very compact. Snug cockpit. Doesn't buffet badly up to 80mph. 140bhp 1.9 auto available. 190bhp 2.8-litre six replaced by new 231bhp 3.0-litre six in spring 2000. 321bhp 3.2-litre M version almost too powerful. New small engine range from spring 1999, with 115bhp 1.9-litre four and 150bhp 2.0-litre six, then 170bhp 2.2-litre six. Improved unlimited-mileage two-year full manufacturer warranty, followed by one-year full dealer warranty from November 2001, making total three-year unlimited-mileage warranty. BMW, Toyota and Ford jointly suffered the fewest breakdowns attended by German ADAC during 2001. BMW had sixth-lowest average cost in warranty claims for cars up to 10 years old in 2002 Warranty Direct index. BMWs generally had below-average warranty repair costs in 2003 Warranty Direct reliability index. (See Reliability Index :: how reliable is your car?
What's bad: 115bhp and 140bhp 1.9-litre fours not really enough except for cruisers. No clever roof like the SLK. Not very sporty to drive. Soft-tops can leak. Optional hardtops offer poor seal for side windows - modification kit available from early 1999. Z3 M Coupé is fast, but aesthetically hideous. Pre-November 2001 three-year warranty required expensive top-up to be comprehensive in second and third years.
What to watch out for: build date from 2001 shown on engine compartment label on top of front nearside wheelarch. Many RHDs were personally imported to avoid long delivery dates and don't have UK three-year dealer warranty. 2.8s imported from other markets may have vulnerable Nickasil-lined bores rather than steel-lined bores. Check fuel tank for damage from bottoming out (very expensive to replace). Front suspension lower ball joints and inner bushes wear, but are comparatively cheap to replace. Service light indicator can easily be reset, so a paid invoice is the only guarantee of a recent service. Check tool kit is all there.
Hope this helps a bit.