What is it?
The M4 GTS is a very expensive, very rare and very, very fast evolution of the BMW M4 coupé, following a lineage of M3 special editions such as the E30 M3 Sport Evolution, E46 M3 CSL and previous-shape E90 M3 GTS. These are all now highly sought after and valued cars among collectors, and BMW hopes this new GTS will join them among the very highest echelons of M rarities.
To that end, a £120,500 asking price and production run limited to just 700 cars - 30 of which will make it to the UK - ensures that only the keenest of the keen will have the pleasure. And if the fixed rear wing, jutting front splitter, extra vents and roll cage don't tell you enough about its track pretentions, the technical spec will.
Thanks to an innovative water injection system, power from the M4's twin-turbo 3.0-litre straight six has been increased from 425bhp to 493bhp, and that's just the start. Carbon-ceramic brakes are standard, the suspension has been significantly beefed up and includes manually adjustable passive dampers, and the wheels wear bigger Michelin Pilot Sport Cup 2 tyres.
For all the stripped-out interior and carbonfibre panels, weight hasn't been reduced significantly, but performance gets a massive boost. With a 7min 28sec Nürburgring lap, the GTS is nearly 30 seconds faster than a standard M4 and comparable with Porsche 911 GT3s in its circuit pace.
What's it like?
It's fierce. If the roll cage in the back and fixed-back racing seats of the no-cost optional Clubsport package don't reinforce the hardcore message, the bark from the titanium exhaust on start-up most certainly does.
Unlike the standard M4, there's less emphasis on multiple driver modes and configurability, although if you want to get the spanners out, you can adjust the aero, ride height and damper settings manually. With reduced soundproofing, there's much more sense of the engine's forced induction, the whooshes and chuffs of the two turbos providing a more exciting and authentic soundtrack than the speaker-enhanced drone of the standard M4. And the noise from the titanium exhaust pipes is outrageous, especially in the attention-seeking Sport and Sport Plus modes.
It's not all style over substance, either. The passive dampers offer far better body control than the electronically adjustable standard ones, while the ride is busy but much better at maintaining a constant contact patch through the tyres. With the Cup tyres warmed through, traction is therefore much, much better than the sometimes wayward standard car, meaning you can exploit the increased power earlier and harder than ever.
Revised steering gear gives you front-end bite to match, feel through the wheel being much improved. Oddly, the GTS is both more accommodating at everyday speeds while feeling much, much more potent at the top end. In short, it's as thrilling and over the top as it looks.
Should I buy one?
Can it really be worth double the asking price of a standard M4? As ever with cars like this, the value somewhat transcends the number on the price list, and for the rarity, exclusivity and established desirability of M specials, the collectors who buy it won't mind.
Looking at it more objectively, is there really another £60,000 worth of ability in the GTS over the regular M4? Although it's not a true homologation machine like the original E30, this is arguably a meaningful demonstration that M can still stand for 'motorsport', rather than 'marketing'.
Okay, it's a track day plaything for those brave enough to risk their investment on a circuit. And the uneducated might mistake it for an M4 in an aftermarket body kit. But under the attention-seeking skin there is real engineering pedigree in this car and convincing proof of the additional potency lurking in the standard M4. Eyebrows will be raised at BMW charging 911 GT3 money for an M4 with a wing, but the fact that it's backed up with a lap time to match Porsche's best proves it's the real deal.
For the rest of us, an updated M4 with some of the steering and suspension mods and a more reasonable price - perhaps a modern equivalent of the much-loved E46 M3 CS - would be a very nice halfway house.
BMW M4 GTS
Location Wiltshire; On sale Now; Price £120,500; Engine 6 cyls in line, 2979cc, twin-turbo, petrol; Power 493bhp at 6250rpm; Torque 442lb ft at 4000rpm; Gearbox 7-speed auto; Kerb weight 1585kg; Top speed 190mph; 0-62mph 3.8sec; Economy 33mpg (combined); CO2/tax band 199g/km, 36%