BMW's HP series of limited-edition hotshot specials has been around since 2005, starting with the HP2 Enduro, Megamoto and Sport - but those were all Boxer twins and, let's be honest, there's just so much you can do with a flat-twin motorcycle engine.
Now the Blue Propeller Guys have announced the HP4, their first four-cylinder high-performance special. It's billed as the lightest four-cylinder sports bike on the market, at less than 200kg ready to go with the fuel tank 90 percent full.
That's because peak power and torque are the same as the 'standard' S1000RR on which this very limited-edition special is based: 142kW at 13 000rpm and 112Nm at 9750, although the torque curve is a lot stronger between 6000 and 10 000 revs.
Unlike the RR, however, you get all that power in all four engine mapping modes - Rain, Sport, Race and Slick - with the same throttle curve, although BMW says the torque curve is noticeably smoother between 2500 and 8000rpm in Rain mode.
Most of the extra mid-range torque is apparently thanks to a new, all-titanium exhaust system with a cross-pipe between cylinders two and three, a controlled acoustic valve and a closed-loop catalytic converter.
It's also 4.5kg lighter than the RR's auspuff, which is really what this bike is all about.
According to BMW this is a genuine homologation special, ready for the track straight out of the crate - which is not to say that it won't make one helluva Sunday morning hooligan tool.
It's also a very selfish bike, strictly a single-seater as issued, although a pillion perch and footpegs are available as aftermarket accessories, for those of us who have partners with nerves of steel - or no nerves at all!
It's also the first production bike to be fitted with dynamic damping control, in which the electronic damper valves are constantly modulated by a range of suspension movement sensors that monitor not only the speed a range of deflection but also the rate of change of those parameters, and adjust the damping accordingly.
FOUR DIFFERENT ABS MODES
The HP4 also comes with Grand Prix-standard Brembo brake callipers and floating brake discs in front, and an upgraded antilock braking system.
As before, it has four different modes for wet surfaces (Rain), roads (Sport), race track with supersports tyres (Race) and race track with slicks (Slick) - in which mode it will let you back the rear wheel into a corner without interfering.
Needless to say, a quick-shifter is standard issue, but the traction control system has also been upgraded; in Slick mode you can tune its setting 'on the fly' to allow for tyre degradation during a race. There's even a launch control function - a first for BMW - in Slick mode, that modulates engine torque to keep the front wheel just kissing the deck while you hold the throttle wide open.
New seven-spoked, forged light-alloy wheels and a new, lighter sprocket carrier save 2.4kg of vital unsprung weight, compared to the 'street version'. The HP4 also runs a special Pirelli Diablo 200/55 ZR17 rear tyre, which allows you to take maximum advantage of the electronic rider aids but which may be difficult to get replacements for in some markets.
KEEPING TRACK OF IT ALL
The instrument cluster has a revised display, featuring the HP4 logo, and an extended range of information and functions, including the dynamic damping, traction control and launch control settings.
The HP4 also looks pretty special; in addition to the monoposto seating it comes with dual-section engine spoiler - longer than the one on the RR - a tinted screen and tiny, faired-in LED indicators, and is finished in a very tasty blue and white livery.
Each HP4 has a small, flat section milled into the upper fork yoke, laser-engraved with the bike's serial number.
WANT TO SPEND EVEN MORE MONEY?
Then ask for the competition package, which adds a longer, enclosed carbon-fibre engine spoiler, blue-anodised wheels, adjustable footrests and folding levers.
The HP4 will be available in South Africa in limited numbers from December 2012; prices, as usual, when the bikes get here but rest assured, they won't be cheap.