The M3 Saloon and Convertible are expected to add 1,300 annual sales to BMW GB’s volumes.

Both share the 420bhp V8 engine which, thanks to BMW EfficientDynamics, is lighter and uses less fuel than its predecessor’s V6 powerplant.

Both are superb to drive, with smooth power delivery and handling as involving as any M-car aficionados would want.

The saloon is the first four-door M3 since the E36 model, which sold for £16,000 less in the mid-1990s, although with far less technology.

The new M3 Saloon’s volumes will be modest – 400 units in a full year, compared to Convertible’s 900 units.

By comparison, M3 Coupé is targeted at 1,900 units annually.

BMW says it decided to offer the muscular-looking saloon as customers are increasingly keen to marry high performance with practicality.

It doesn’t have the coupé’s carbon roof, but back seat occupants get more room: there’s 20-litres extra space in the boot, and it’s still rammed with technology and comforts.

The fourth-generation M3 Convertible costs £9,320 more than its predecessor yet is a much better prospect in the showrooms.

“On the face of it, the new price looks expensive but it’s misleading because it includes features that would cost more than £5,500 if they were fitted as options.

We’re also offering a lot more technology,” said product manager David Cantle.

Its electro-hydraulic three-piece roof takes only 22 seconds to fold itself neatly away in a boot that also manages to hold 210 litres of luggage.

Buyers can specify an optional M DCT dual-clutch transmission, which improves acceleration, economy and emissions over the manual.

Fact file

Price: £54,760 (convertible) £49,415 (saloon)
Engine: 4.0-litre V8: 420bhp
Performance: 0-62: 5.3 sec (conv), 4.9sec (sal); top speed: 155mph (both)
Transmission: 6sp man, 7sp M DCT auto
Efficiency: 23.0mpg; 293g/km CO2 (conv); 22.8mpg; 295g/km CO2 (sal)
CAP RV: 52% (conv), 50% (sal)
Rivals: Mercedes-Benz CLK, Mercedes-Benz C63 AMG, used Audi RS4 Strengths: Performance and practicality, usability
Weakness: M DCT costs £2,590, fuel bills