I'VE always thought that BMW diluted its top sporting M designation by attaching it to lesser models.

Originally, there were M3, M5 and M6 models that were all the top cars in their respective ranges - set up for out and out performance and devil take the hindmost.

Of course, those models still exist in each of the company's ranges, and there are more of them - including the M4 coupe and convertible.

The most recent model to bear the name is still very expensive, so I'm going to focus on the M4 built between 2014 and 2020.

It replaced the previous M3 coupe and shares all its running gear with the M3 saloon, estate and five door coupe.

So if you want a coupe or convertible you buy the M4 and if you want a saloon or estate you buy the M3.

At one time, BMW's engineers pooh-poohed the idea of using turbochargers in these top models, increasing the size or the power units instead so that at one time, they were powered by glorious V8s that had a soundtrack to die for.

Now though, in the need for ever lower emissions and higher economy, twin turbos are added to the company's superb three litre straight six, giving this storming supercar even better performance from no less than 425bhp..

Top speed is limited to 155 miles an hour with either six speed manual or seven speed dual clutch automatic gearboxes, and the auto is marginally quicker on acceleration because of superbly quick changes made in a fraction of a second.

Zero to 60 miles an hour takes a mind-blowing 3.9 seconds and economy is still rated at an astonishing 27 miles per gallon.

Obviously, such power and speed could lead to unwanted trips into the greenery but here there is a wide array of electronics to help you keep on the tarmac - from an electronically controlled limited slip differential, to active dampers that can be controlled by the driver.

Of course - this is a BMW - its rear wheel drive and this helps towards perfect 50/50 per cent weight distribution front to rear.

That in turn means that as well as superb performance in a straight line, it has excellent balance in the corners, and with immense grip and roadholding, plus beautifully tactile steering, it handles like a dream.

So swift is it in every response, that to the enthusiastic driver, everything seems almost like an extension of thought!

The adjustable dampers mean that when driving harder, the suspension can be made firmer to aid roadholding even more, and all in all, this is a car to be savoured and enjoyed.

The only downside is that the suspension is pretty firm to start with, so the ride can sometimes be fairly lumpy, and since there's a fair amount of road noise from the massive tyres on the motorway, longer journeys can be tiring.

There is basically just one trim level and that comes with just about everything anyone could wish, including leather covered and heated electric seats, parking sensors, traction control, and sat nav.

Pay about £25,100 for a '19 19-reg Coupe manual, or £29,220 for a '20 20-reg Convertible automatic.