The continuous hum of an anticipatory drum roll has been emanating from Infiniti for an infuriatingly long time now, always threatening but never actually making way for the main event. But now, at last, the maker finally raises the curtains on arguably its most important model: the 5 Series rivalling Infiniti M.

Its form isn't actually new - we've seen it a few times - but the spec sheet is. In a detailed press release, Infiniti has unveiled exactly how its new executive player is going to conquer a segment that has until now comprised three key Germans and a Japanese also-ran. If the M is destined to elevate itself above the very good but often overlooked Lexus GS and into the main pack, it will have to be brilliant. And probably cost effective too.

Sadly we don't know about that last point yet, because amid telling us about the newcomer's forest-inspired air freshener, the maker has neglected to mention the cost of the thing. Mind, there's plenty of time between now and its September 2010 launch.

Regardless of price, Infiniti seems determined to assault the pack on all fronts; the M promises to be vast yet agile, quick yet economical, well equipped and Germanic in tactility but with very Japanese build integrity. Power comes from V6 petrol and diesel units, the former a 3.7-litre with 316bhp and 266lb.ft of twist, and the latter with... oh, they'll tell us that later too. Hmm. A petrol-electric hybrid will complete the trilogy at some stage.

A seven-speed automatic with paddle shifters will be standard, offering eco, sport, snow and standard modes, and on the handling front there's a speed-sensitive steering rack, optional four-wheel steering and Dynamic Cornering Enhancement that brakes each wheel individually to aid fast point-to-point driving. The eco mode of the aforementioned gearbox mapping will, when selected, physically push back the accelerator pedal when the driver is wasting fuel.

Under the 'Safety Shield' banner, the M gets blind spot evasion technology that can automatically steer away from a car in the blind spot, as well as lane departure warning, seat belt pre-tensioners and frontal collision warning.

Infiniti has poured much effort into making the cabin as alluring as possible, even employing researchers to specifically look at the softness of the interior plastics and shape of the switchgear for maximum 'human warmth'. We're also promised room for five adults, although weight is kept down by using aluminium for the door skins, bonnet and boot lid. Quilted leather is standard and the wood veneers are hand finished. It gets Active Noise Control to cancel out the lowest, most unpleasant frequencies in the cabin, and the air conditioning 're-creates the gentle breezes and subtle scents of an environment known to promote alertness and relieve stress: the forest'.

And that seems like a good thing to leave you with.