Watch the Maddest Lap Record in Modern Motorsport

The Isle of Man Tourist Trophy motorcycle race (better known as "The TT") is one of the last bastions of true road racing. We don't have a car equivalent any more, tarmac rallies and retro recreations aside. That didn't stop Subaru from doing an exclusive sponsorship deal to set a time around the notorious 37.73-mile Snaefell Mountain Circuit in a car. 2016 is the final year of that deal, so given that Subaru already holds the lap record for cars, they decided to make life very difficult for the next car company who might come along to set their own...

In 2014 the record was set by rally driver, James Bond stunt driver and general hot shoe Mark Higgins in a near-standard WRX STi whose only modifications were a rollcage, fire extinguisher, higher-performance tyres, adjusted suspension settings and little else. All stuff you could do in a shed to your own car. The time was 19:26, an average speed of 116.47mph around a track big enough to fit most of the car world's race tracks inside it, including Le Mans and the Nürburgring - not surprising given that it covers half of an island...

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To put their stamp on this little PR stunt once and for all, Subaru called on their old friends Prodrive, who previously engineered title-winning WRC cars for them. Together they created a beastly one-off special of the WRX STi specifically to tackle the towns, mountain passes and countryside back roads of the Isle of Man... not to mention the jumps. "Oh, you want to be careful over these jumps, because at this kind of speed the car could actually fly," so says local bloke Mr. Higgins, who was drafted in once again to do the job only people bonkers enough to race motorcycles normally do.

The car's 2.0-litre turbo boxer-four engine is tuned up to 600 horsepower and 590lb/ft despite using the standard block and cylinder heads. This involved bespoke motorsports turbo, intercooler, cams, pistons, con rods, crankshaft and gaskets. Unlike the rally engines Prodrive normally put together, this one revs up to well over 8000rpm! Having straight-through exhaust pipes means it is also LOUD.

the Gran Turismo logos are curious - possible new content in GT7 maybe???

Unseen in these photos I took at Goodwood FOS last weekend (coming soon!) is that the beastly boxer four is connected to an old WRC-grade six-speed semi-automatic gearbox co-developed with Xtrac. There's a paddle on the right-hand side of the wheel to change gears, but a pair of pneumatic actuators are actually pushing an H-pattern gear shift around when he pulls or pushes it, the idea being that if he spun he could reach down and shove it straight into first gear with the stick, rather than losing valuable seconds shifting down from, say, 5th to 1st and waiting for each gear to engage before selecting the next one.

So that's the engine, but the rest of the car needs upgrading to match it. The suspension is custom but includes WRC-spec linkages and four-way adjustable dampers. To bring it from 174mph to about 30mph as quickly as possible - a genuine requirement - there are vast AP Racing brakes with six-piston calipers squeezing 355mm discs. Directing the power from the gearbox to the four wheels are an LSD on each axle, via a hydraulic active centre diff. Finally all that torque rotates 18" wheels shod in BTCC-spec Dunlop slick tyres - not the soft compound, because that wouldn't even last a single lap of Manx torture!

Lastly, along with aerodynamic flares, there is a driver-activated DRS rear wing (although it won't lean back if sensors detect the car is rotating). It's so effective that on the long open sections the car could really do with a seventh gear, so quickly does it hit the limiter in sixth.

The result of all this and a few attempts at the lap while the bikers had lunch, is a new lap record of 17:35.139 at an average speed of 128.73mph. Once you've seen the video up top, you'll know how mad that is. But is it as mad as a motorbike doing it in 16:53.929 at 133.962mph? Certainly the consequences are worse for making a mistake on the bike - not least as it tops out at around 200mph on the mountain - but one could argue that threading a significantly wider new Impreza through villages at damn near the same average speed without lifting your toe off the throttle takes equal amounts of commitment.

Either way, the next car company to come along has a serious gauntlet to pick up now.