The E63 AMG and M5 are merely baselines for these extraordinary cars

For the most extreme tuning companies and low-volume manufacturers, supersaloons such as the E63 AMG and M5 are merely the baseline from which to create something truly extraordinary. For proof look no further than the German powerhouses of Brabus and G-Power, who are waging übersaloon war to see who can build the world’s fastest – and most gloriously irrelevant – supersaloon.

G-Power M5 Hurricane RS

Though less well known than Hartge, AC Schnitzer and the like, G-Power has been tuning BMWs since 1983, and recently it has become an increasingly potent force to be reckoned with on the ‘world’s fastest…’ scene.

G-Power’s breakthrough car was this, the M5-based, 740bhp Hurricane RS. Lapping the ATP test track in Papenburg, Germany, this twin-supercharged monster achieved a GPS-verified top speed of 367.4kph, eclipsing the Mercedes CLS-based Brabus Rocket to officially become the fastest four-door in the world.

An evolution of the ‘standard’ 720bhp G-Power Hurricane – itself a former record-holder with a top speed of 360kph – the RS gained its extra 20bhp and the vital 7.4kph thanks to a pair of specially developed superchargers. Currently these haven’t made it to G-Power’s regular build programme, but the regular Hurricane is surely quick enough to be going on with.

The M5’s 5-litre V10 is a screamer as standard, but lightweight Mahle engine internals and a pair of ASA superchargers complete with huge intercoolers elevate the Hurricane’s motor to a whole new level of madness, with 720bhp between 7500 and 8200rpm, along with 516lb ft at 7200rpm. Clearly G-Power’s evolution of M Power’s F1-inspired V10 still likes to rev a bit…

How the seven-speed SMG transmission copes with this onslaught is anyone’s guess, but the performance gains become more and more apparent the faster the Hurricane goes. As you’d expect, it’s not too hot from a standstill, reducing the standard M5’s 0-100kph time by just 0.5sec, to 4.2sec, but G-Power’s flagship is devastating to every significant increment from this point on, taking just 10sec to hit 200kph, which is 5sec quicker than the M5. A sub-30sec run from zero to 300kph cements the Hurricane’s legend status.

In production trim, G-Power sees fit to electronically limit the Hurricane’s top speed, although at 341kph it’s somewhat less timid than BMW’s 250kph limiter. Once G-Power’s engineers have fully evaluated the latest high-speed tyres from Continental they plan to de-restrict the Hurricane altogether. If we were spending $ 395,000 on the world’s fastest saloon, that’s no less than we’d want, even if the opportunities to experience the benefits are virtually zero.

What next? Well, ominously for Brabus, G-Power’s top brass believe they’ve just got started, at least according to a brilliantly provocative statement on the company’s website, which says there’s plenty more to come from the twin-supercharged V10: ‘We can raise the boost level up to 1.0bar and more. We can still improve, if we see the need for it. We are curious if this will be necessary…’

Over to you, Brabus.

Brabus E V12 ‘One of Ten’

G-Power might be the current record holder, but it seems the Hurricane RS’s title is on borrowed time if Brabus’s claims for the E?V12 ‘One of Ten’ are true. Based upon the already ballistic E?V12, this strictly limited edition version has even more power and torque, together with the hypersaloon equivalent of a speed skiing suit. In short, it’s utter saloonacy.

At a smidge under $ 660,000, the E?V12 ‘One of Ten’ is searingly expensive, but there’s no question that officially authenticated world records aside, this is the killer Top Trumps card every Eastern European oligarch will want up his immaculately tailored sleeve.

And who could blame them? Every aspect of the car is extraordinary, from its 6.3-litre, biturbo engine (based on the 5.5-litre V12 normally found in the S600) that thumps out 789bhp at 5100rpm and a seismic 1047lb?ft at 2100rpm, to its specially streamlined bodywork – complete with so-ridiculous-they’re-almost-cool rear-wheel spats – and, of course, its claimed 370kph top speed.

In days gone by the E?V12 was so over-powered you could plant your foot to the floor on a dry road and literally spend the next few minutes at walking pace while the ESP warning triangle blinked like a strobe light on the dashboard. Nowadays tyre and traction control technology has caught-up a little, so while it’s doubtless still possible to cremate the rear rubber at will, the ‘One of Ten’ can also put its torque into the trembling tarmac.

From a standing start it’ll hit 100kph in just 3.7sec, 200kph in 9.9sec and 300kph in a barely believable 23.9sec. Not only does that blow the Hurricane into the weeds, but the E?V12 would make a severe nuisance of itself against anything this side of a Bugatti Veyron.

Perhaps the most revealing nugget of information about the ‘One of Ten’, indeed the most revealing thing about the whole world’s fastest saloon obsession, is that its massive torque figure is purely for willy-waving purposes only. When fitted in the car, the motor is reined-in electronically to exactly the same 811lb?ft torque peak as the vanilla ‘996lb ft’ E?V12. Oh, and much like G-Power, Brabus electronically limits the top speed on the grounds of tyre safety. However, in a petty but extremely amusing bout of brinkmanship, the boys from Bottrop deem 350kph to be harmless, thereby ensuring a 8kph advantage over the Hurricane. We get the feeling this one’s going to run and run.