As 50th birthday presents go, the new BMW M4 CSL certainly seems a fitting half-century celebration for the firm's athletics division.

Enticingly exclusive and with the promise of tangibly improved dynamics, it should be the latest in a long line of successfully enhanced M cars, following on from the similarly conceived BMW M5 CS - the only car to achieve a five-star Autocar road test verdict last year. 

But you can’t just bandy the ‘Leicthbau’ name around like nobody’s business. Even with just two carbon-shelled seats and ultra-light chassis components in place, this track plaything weighs some 240kg more than the last car to bear the badge - albeit while packing around 200bhp more power. 

Perhaps the fact that the standard BMW M4 Competition already goes heavy (no pun intended) on the carbonfibre and trimmed-down tech means that there was less room for manouver with this new special edition. Plus, there's the unavoidable but no less palletable truth that cars simply have to be heavier now, compared with 20 years ago, given the modern consumer's expectations of refinement and safety. 

Lose the bells-and-whistles sat nav, then, you might cry, or the wireless phone charger. But this is a near-£130,000 car - it can't really afford to lose any marks for real-world usability, even considering its track focus. 

The snarling M4 Competition is already searingly quick and more than agile enough to give prospective Porsche 911 Turbo owners pause for thought, but does the new CSL go far enough in its reinvention to face off with the venerable Porsche 911 GT3

Here’s hoping its limited build run won’t discourage owners from finding out.