During development, BMW hid its latest special edition M car in plain sight: the MotoGP safety car became the M4 GTS. All that track time policing mad motorcyclists has paid off, and some.
In the metal
The GTS is an M4 with more attitude. The jutting chin splitter (adjustable for track use) and the rear wing mounted on CNC-machined aluminium struts on the boot look like they've been borrowed from a super-touring car. The track reference is relevant, too, as BMW's M division has made its new 700-run of GTS models for customers who like to spend weekends shaving tenths off their lap times. Like the MotoGP safety car that previewed it, the M4 GTS gets a trick water injection system, aiding combustion and cylinder cooling, allowing for a earlier spark, higher compression and more power, without penalising economy.
Power grows to 500hp, while torque is up to 600Nm too, which, allied to some significant weight reduction, makes for a far more accelerative and intense M4. The suspension has a track bias too, the coil-over set-up offering lots of individual adjustability, allowing it to be changed to your preferences and the track you're at. Weight has been lost thanks to the binning of the rear seats, the addition of lightweight front bucket items, a unique carbon fibre bonnet and a titanium exhaust. M division's mass reduction hasn't stopped there, going so far as to chuck out the standard door cards for lightweight ones with simple straps, and if you choose the (€12,000 before VRT) carbon fibre wheels you'll shave a further 7kg off the unsprung weight. There's a Clubsport option as well that adds a cage, proper six-point harnesses and a fire extinguisher. Basically, the GTS is a thinly-disguised racer with number plates.
Driving it
Given M's intent for this car, it's hardly surprising that our first drive is exclusively limited to a track. Specifically, the Circuit de Catalunya, 4.65km and 16 corners of bumpy Spanish circuit. Buckling into a car with six-point seatbelts always ups the anticipation, though be sure to close the doors via those simple straps before tightening the belts or you'll be loosening them off again quickly. Though more overtly track-focused than the regular BMW M4, thanks in large to the bucket seats, that (free) optional cage and no back seats, the cabin is still familiar. There's a GTS badge on the dash if you've somehow forgotten that this isn't an ordinary M4, though thumbing the engine start button leaves you with no doubt.
The titanium exhaust doesn't just remove mass; it adds sound, giving the 3.0-litre twin-turbo six-cylinder engine a far more guttural, race-edged note. It varies depending on which drive mode you're in, but select the most focused and the exhaust is loud enough to trouble lots of track day drive by noise regulations. Above the looks, that sound and the promise of more power from that clever water injection system it's the first turn of the steering wheel that reveals the biggest change to the M4's make up. A standard M4 feels mute in comparison. Even trickling down the pit lane it's obvious that the geometry revisions, different steering mount specification, reduced unsprung mass and those coil overs are what define the GTS. The steering is far more immediate, the feel through the rim increased markedly, though exiting the pits and asking that 3.0-litre engine for more reveals that the chassis changes are backed up with some very tangible improvements in not just the engine's output, but its response, too.
There's a reduction in internal inertia of the engine thanks to a lighter crankshaft, while the entire engine benefits from a weight reduction thanks to the loss of the cylinder liners - BMW M instead using an arc-sprayed coating. There's an aluminium oil sump too, though the most innovative addition is the water injection system, which injects distilled water into the intake plenum chamber, cooling the intake air, reducing pre-ignition knock and allowing an increased effective compression ratio and bigger boost pressure. Those injectors are fed by a water tank in the boot, though it only operates at 5,500rpm and above. Nonetheless, the other engine changes are apparent across the lower arc of the rev counter's sweep. There's a more forceful shove in the back from low revs and the throttle is far sharper than the standard M4's - the loss of some rotational mass means it's even more eager to rev, too.
If the faster, more responsive engine in the M4 GTS takes the M4's performance to a different level, the chassis revisions allow you to exploit it more readily. The aggressively track-orientated Michelin tyres have been developed specifically for it, and they deliver mighty grip and help with the incisive turn in. They can be made to relinquish their hold though, and the M4's transition from grip to yaw angles is so beautifully progressive to make it feel like the most natural thing in the world. There's plenty of adjustability on the throttle too, so it's easy to set up the M4 GTS before a corner by a slight lift, before powering through it with as much lock as you dare. That's with the electronic assistants still in attendance, though they can be switched off entirely should you desire. If there's a weak link in the make-up it's the dual-clutch transmission, which lacks the speed and precision of some of its newer rivals' systems, though perhaps it stands out because of the GTS's immediacy in every other area. Its sharpness is its defining feature, and one that's hugely welcome as sports and performance cars get ever more remote.
What you get for your money
The BMW M4 GTS might be stripped of the likes of rear seats, but otherwise you'll not want for anything. BMW is debuting new light technology front and rear, too, though they'd get more column inches if there wasn't more to talk about in terms of the drive. With just 700 being built, and every one accounted for, it's not just a sensational plaything for a wealthy few, but about as solid an investment as you could make.
Summary
Like all M specials before it the BMW M4 GTS has delivered a very special driving experience. It's arguably to the detriment of the standard car though, which, crazy as it sounds, feels leaden in comparison. We'll need to drive the GTS on the road to really reveal the full extent of its ability, but our short few laps in it left us wanting more. Lots more.
