Rare BMW M3 pocket-rocket up for grabs

The M3 Convertibles were the world's fastest four-seater soft-tops of their time.

One of the rarest BMW M3s built in the model's illustrious 20-year history is going under the hammer at an auction in Melbourne next Monday.

Though 800 examples of the E30 BMW M3 Convertible were built between March 1988 and June 1991, only 137 of these were equipped with the most powerful 160kW (215bhp) incarnation of motorsport engineer Paul Rosche's 16-valve 2.3-litre four-cylinder engine, a design based on BMW's Formula One experience.

And only one of the 137 convertibles is believed to have been painted Misano Red (colour code 236), a shade normally reserved for the high-performance Evolution 2 and Ravaglia versions of the M3.

Add an equally rare optional factory hardtop and the 1990 M3 Convertible being auctioned by Shannons becomes a desirable and collectable BMW at its expected price of A$38,000-44,000 ($45,000-52,500).

Unveiled at the 1985 Frankfurt motor show, the M3 was a pocket-rocket built by BMW's motorsport division to homologate the E30 3-Series for the European Touring Car Championship.

Using what was essentially the 24-valve head from the M-Sport straight-six engine (minus two cylinders) mated to the block of the four-cylinder M10 engine, whose origins dated from the company's successful 1.5-litre turbo Formula One programme, the M3's motor developed an impressive 145kW (195bhp) from 2.3-litres.

With a Getrag close-ratio five-speed gearbox, firmer suspension and additional downforce from the aerodynamic aids, the original M3 was one of the world's most dynamic performance cars.

With a quoted top speed of 239km/h, the limited run of the M3 Convertibles became the fastest four-seater soft-tops of their time.

More luxurious and generally better equipped than its closed M3 sibling, the Convertible featured a leather interior with electrically operated hood (as found on the 325i Convertible) and combined the best of both worlds - race-bred performance and refined open-air motoring.

The vehicle being auctioned by Shannons was originally delivered to a German customer and spent time in Holland before being converted to right-hand drive by Birds, a British BMW outlet.

It comes with leather interior, electric windows, factory hardtop, Hartage 16-inch alloy wheels, an electrically operated hood and an Evo 2 spoiler.