The 4 Series Convertible follows the Coupe launched just a few months ago, while the high-performance M4 Coupe Concept, which made its debut at Pebble Beach recently, is appearing at an international exhibition for the first time.

The new model replaces the former open-top 3 Series as BMW looks to make the model more exclusive – a strategy also employed with various models of the 1 Series, which are being re-christened as the 2 Series.

The 4 Series Convrtible is already in production and is set to go on sale next March, initially as the 435i, 428i and 420d. Further engines will be added soon afterwards.

Dr Ingo Lasslop, the head of product management for both the 2 and 4 Series, told news agency Headlineauto the emphasis with the new car was greater acoustic comfort in the cabin and improved accessibility for loading.

The three-piece retractable hard top has a noise-absorbing roof liner which lowers sound levels in the rear of the cabin by two decibels and makes normal conversation possible at speeds of 100mph, says Lasslop. There is also a new design of wind break which improves the comfort of occupants when the car is being driven top-down.

BMW's compact convertible now has a load assistance switch which raises the rear of the hard top when the car is closed to make it easier to through-load into the cabin.

The US will be by far the major market for the car, followed by Germany and the UK, but China is coming up on the rails. These four countries will account for two-thirds of production.

The importance of the Far East, and particularly Japan, for high-performance cars was decisive in BMW choosing Tokyo for the first show airing of the M4 Coupe Concept. If BMW follows its usual chronology, we can expect to see a production version early next year, at either Detroit or Geneva, according to Headlineauto.