It has to be said: the BMW Z3 is not as good as the new Z4. But with new Z4s fetching £5,000 over list price and used Z3s available for under £20,000 the Z3 is good enough to appear on the shortlist of anyone who fancies buying a two seater convertible.

The Z3’s character is defined more by the choice of engine under the bonnet than the BMW badge on its top. The four-cylinder is likely to disappoint all but the most sedate of drivers. But step up to a six-cylinder and the car begins to offer a more typical BMW driving experience.

The smallest of the six-cylinder units, the 2 litre, produces 170bhp, reducing the driver’s chances of being embarrassed at the lights by the rep in a VW Golf diesel.

Then come 2.2, 2.8 and 3 litre units, all smooth straight-sixes, the pick being the 3 litre. Introduced in June 2000, its 231bhp endows the car with a 149mph top speed and fuel economy that nudges 30mpg.

Topping the Z3 range is the rather clumsily named Z3M. With an engine straight out of the M3 but a body weighing some 200lb less it reaches 60mph in just over 5sec. With 1997 examples changing hands for about £27,000 (the same price as a new MGTF), the car has little competition in its ability to deliver performance and quality at this price.

In common with most BMWs very few Z3s left the factory with standard specification, many buyers spending thousands on options. But some of these add little to second-hand value, while others are considered essential. Most desirable are leather upholstery (with the roof down a cloth seat gazing out from the cabin destroys street cred), air-conditioning, electric seat adjustment and electric roof.

Base model 1.8 Z3s came with steel wheel rims but fortunately most buyers stumped up for alloys — cars without should be £1,000 cheaper. BMW also offers an optional hard top, which looks unexpectedly good on the car: expect to pay about £1,000 extra for a car that has one.

The Z3’s road manners are defined by the combination of engine size, wheels and suspension. A standard 1.8 or 1.9 feels more the ponderous cruiser than a dynamic sports car. But drive a larger-engine car shod with 17in alloys and M sports suspension and its character is transformed.

High speed cruising is best done with the roof up to avoid buffeting, but at lower speeds the large screen and low seating position provide a civilised environment. Dashboard and switchgear is classic BMW — large plain dials and well laid out minor switches provide no nasty surprises, and trim fit and finish should be tight and rattle free.

On any convertible the condition of the roof is important and affects the car’s value, so spend some time to check it carefully. The Z3 is prone to leaks around the side windows, particularly on cars that have spent their lives outside. The same is true of the hard top, so make sure you see it in place and drive the car with it on before you part with your money.

Choose a used Z3 with a strong engine, good specification, finished in an attractive colour and trim, and it will provide open-top motoring, from a prestige manufacturer, at a reasonable price.

On the forecourt

VITAL STATISTICS

Model: BMW Z3
Engine: Six-cylinder, 2979cc
Power: 231bhp
Transmission: Five-speed manual
Fuel: 29.7mpg (combined)
Acceleration: 0 to 62mph: 6.5sec
Top speed: 149mph

Upholstery: Leather is essential

Hard top: Check seals on optional hard top

Exhaust: Six-cylinder models distinguished by twin tail pipes, Z3M gets four.

Fuel tank: Mounted low so it can be prone to road damage and is expensive to replace.

Options: Few cars have standard spec Ð look at original sales invoice to confirm factory options.

Wheels: Steel wheels standard on smaller engined cars but 17in alloys standard on Sport models.

Tyres: Check they're all the same make and have plenty of tread.

Passenger airbag: Standard since July 1999.

Imports: High desirability led to many grey imports, check with BMW to confirm car's build date.

Bumpers: Low seats and a long bonnet make bumpers prone to scuffs.

Warranty: Three-year unlimited mileage on cars since November 2001.

Service history: Full history is essential, insist on viewing all original invoices.

THE ONE TO BUY

BMW Z3 manual, 2000 W-reg with 30,000 miles and full BMW service history. Pay £16,450 at a dealer or £15,250 privately.

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OR FOR SIMILAR MONEY...

1999 T-reg Audi TT 225bhp Roadster
2003 52-reg MGTF 1.8 VVC 160
2000 V-reg Mercedes-Benz SLK 230K
1996 P-reg Porsche Boxster 2.5
2000 X-reg Honda S2000

VALUES: BMWZ3 3.0 Sport models worth £500 more, automatics worth £600 more. Source: estimates based on confidential CAP black book prices. 'Trade' is what a dealer would pay to buy your car; 'retail' is what you would pay a dealer