AT FIRST GLANCE it would be easy to dismiss the second-generation X5 as a lightly massaged follow-up to BMW’s first super-successful foray into the luxury SUV market.

Indeed, given the fact that a staggering 616,867 examples of the original E53-series X5 were produced between 1999 and September 2006 – and that about 16,000 have been sold in Australia since 2000, making it the top-selling luxury SUV both here and globally - it would have been easy for BMW to take the if-it-ain’t-broke-don’t-fix-it approach and rest on its laurels.

Beneath the new E70 X5’s all-new sheetmetal, however, lies a significantly more rigid chassis, redesigned engines, improved transmissions, upgraded suspensions and a much bigger, more upmarket interior that, for the first time, offers seating for up to seven occupants. What’s more, all this comes at no extra cost or weight, except on V8 variants.

BMW says the first X5, which competed against just five other rivals in a luxury SUV segment that attracted around 5000 annual sales, was successful because it was painstakingly researched and engineered.

True to form, the Munich car-maker says it has taken no short-cuts with its replacement, which faces competition from no fewer than 14 models in a class that’s swelled to about 21,000 sales annually.

Despite that, BMW Australia is confident the new X5 will prove even more popular than its forbear, which defied established model cycle tradition by having its best sales year in the twilight of its lifespan in 2005, when 3225 were sold.

Having embarked on a “traveling roadshow” with an example of the new X5, which has been shown to dealers and prospective customers since last October, BMW Oz expects to sell 2600 new X5s this year following an official April 16 release, which equates to annual sales of around 3500.

At that rate X5 would easily continue to be Australia’s top-selling luxury SUV – despite new competitors in Mercedes’ MkII M-class, the all-new Audi Q7 and facelifted versions of Volvo’s XC90 and Porsche’s Cayenne – and BMW already holds 600 official deposits following the reveal of (higher) pricing in February.

Of the three-variant E70 range, however, only the X5 3.0d turbo-diesel and 4.4i petrol V8-replacing X5 4.8i will be available from next month, with the entry-level X5 3.0si due on sale in June.

As usual, BMW says stocks of the new model will be in short supply from the world’s only X5 factory, at Spartanburg in South Carolina, where the Z4 roadster and coupe are also manufactured. Around 50 E53 X5s currently remain in dealer showrooms.

Bigger, stronger, more powerful and more fuel efficient - yet virtually the same weight - the new X5 is claimed to offer even better on-road dynamics, improved interior functionality and higher levels of comfort and exclusivity.

BMW’s first ever seven-seat model rides on a 113mm-longer wheelbase (now 2933mm) and 68mm and 75mm wider wheel tracks (1644mm front and 1650mm rear respectively). Significantly, the body is 187mm longer (4854mm), and both width (1933mm), height (1766mm) and rear overhang (1062mm) are also up.

Inclined bodysides, a rising sill line, shorter roof, steeper D-pillar angle and more sloping front and rear glass give the new model a rounder, less SUV-like appearance that’s similar to the smaller X3, while a pronounced kidney-shape grille, dual circular-themed headlights with daytime running lights, L-shaped tail-lights (with two-stage brake lights and LED lighting) and dual exhaust outlets that exit through the rear bumper continue as trademark X5 styling cues.

Inside, there’s a horizontally themed dashboard atop a vertical centre stack and flanked by convex outboard air-vents. The information display is mounted higher than before (in line with the new instrument panel) and all controls are angled further towards the driver cockpit-style.

The standard electric parking brake, main i-Drive system controller and new balljoint-mounted gearshifter (with push-button Park mode selection) are located close to hand on the lower console. Other new features include extendable sunvisors, a butterfly-lid glovebox that also houses a standard six-CD stacker and “pearl gloss chrome” highlights. Six leather colours and four interior/décor colour themes will be available.

Rear passengers get B-pillar-sited air outlets and an extra 40mm of legroom to now easily accommodate tall adults, but the third row seating option is officially suitable only for passengers shorter than 170cm and is in reality an occasional-use kids-only zone.

Apart from replacing the standard space-saver spare tyre with a “mobility kit”, the rear twin seat costs $5000 on all variants but the flagship 4.8i (on which the cost is $3000), which includes a folding/tumbling second-row seat, additional air-conditioning ventilation and the fitment of self-levelling rear air suspension, which is standard on the 4.8i but costs $2000 on lesser (five-seat) variants.

Underneath all this is a redesigned monocoque chassis that, at 27,000Nm/degree, is claimed to be 15 per cent more torsionally rigid than its predecessor’s – despite its much larger footprint, the exclusive use of heavier (fourth-generation) run-flat tyres and the fitment of an all-new double-wishbone front suspension and modified four-link IRS.

The employment of cast alloy lower front suspension struts, a magnesium dashboard carrier, an aluminium bonnet and a one-piece plastic front bumper/quarter panel helps reduce kerb weight, which in the case of the all-alloy turbo-diesel engined X5 3.0d remains unchanged at 2105kg.

At 2170kg, the 4.8i, which also comes with more standard equipment, is 50kg heavier than the 4.4i, while the base 3.0si X5 is marginally heavier at 2050kg. BMW claims best-in-class aerodynamics and reduced lift, with the Euro-spec 3.0si offering a 0.22Cd drag coefficient.

Fitted with 20-inch alloy wheels, X5 series development project manager Albert Biermann says the new 4.8i laps the Nurburgring’s gruelling Nordschliffe circuit a whole 10 seconds faster than the previous 4.6is flagship.

That’s without the use of X5 optional new Adaptive Drive suspension system, which combines the Dynamic Drive variable-rollbar system available in 5 and 7 Series models with a new EDC variable damping system – all of which is controlled via a new 20 per cent faster high-speed data BUS transfer system dubbed FlexRay, which comprises ECUs for each wheel. Adaptive Drive is a $6700 option on all variants.

As the first model to combine the xDrive all-wheel drivetrain with BMW’s optional Active Steering system, the new X5 is claimed to be “more clever than any previous BMW”. xDrive directs 60 per cent of torque to the rear wheels in normal conditions, but can send up to 100 per cent of torque to either axle.

An upgraded two-stage DSC stability control system (which can still be fully deactivated) adds the ability to divert torque across each axle, but the new X5 continues without the option of an ML/GL-style low range transfer case or Q7-style adjustable air suspension.

Unlike the current X5, the new model is exclusively auto-only and comes fitted with an upgraded ZF six-speed Steptronic self-shifter that’s claimed to be 50 per cent quicker-shifting. A new torque converter is said to improve fuel consumption a further three per cent.

With third-row seats in place just 200 litres of luggage space remains and the 90-litre under-floor compartment is deleted. With them folded flat there’s 620 litres – extending to 1750 litres with the middle row folded – 22 per cent or 110 litres more than before. The tailgate remains horizontally split and now features a shorter lower section to allow better access to the 100mm-longer cargo space. All E70 fuel tanks hold 85 litres.

Opening the new X5 range is the 3.0si, powered by BMW’s latest Valvetronic-equipped (but not direct-injection) 3.0-litre 24-valve magnesium-alloy petrol inline six. It develops 200kW (up 18 per cent) at 6650rpm and 315Nm of torque (up 11 per cent) from 2750rpm, and sprints to 100km/h in a claimed 8.1 seconds in auto-only guise. Top speed is quoted at 210km/h and combined EC fuel consumption is 10.9L/100km.

The E70 X5 3.0si auto carries the same price as the outgoing 3.0i auto - $85,000, and features front and side airbags for front-seat occupants and head airbags for front and middle-row passengers, plus stability/traction control, cornering brake control, anti-lock brakes and five (or seven) three-point seatbelts.

Matt black roof-rails, 18x8.5-inch alloys with 255/55 R18 run-flat tyres, Nevada leather trim, 60/40-split/folding second-row seating, luggage net, multi-function leather steering wheel, foglights, rain-sensing wipers, door-handle lighting, anti-glare interior mirror, cruise control, hill descent control, front/rear parking sensors, dual-zone climate-control, part-power front seat adjustment, front/ear cupholders, stop/start button, power mirrors, one-touch power windows, trip computer, remote central locking, 6.5-inch monitor and a BMW Professional AM/FM/MP3/six-CD player are also standard X5 features.

For $94,500, the X5 3.0si Executive adds the Professional navigation system with 8.8-inch colour screen, DVD/TV player and voice recognition (a $7000 option on base variants), fully powered front seats with driver’s memory ($2500 etc), a rear-view camera ($1000 on non-Exec variants), Bluetooth preparation with BMW TeleAssist ($500 on 3.0si/3.0d), and different-style 18-inch alloys.

The X5 3.0d is priced $1800 higher than the petrol six at $86,800 and is powered by a new all-alloy 24-valve common-rail turbo-diesel inline six that delivers 160kW (up 10kW) at 4000rpm and 500Nm of torque (up 20Nm) at 1750rpm. It offers the same 210km/h top speed as the petrol six, but slightly slower 0-100km/h acceleration (8.6 seconds) and reduced fuel consumption (8.7L/100km).

Like the base 3.0si and 3.0d, Executive versions of both the petrol and diesel six are identically equipped, with the latter priced at $96,300.

At the top shelf of the new X5 range is the 4.8i, which replaces the current 4.4i and raises the price of V8 entry by a significant $6800 to $118,300.

On top of the six-cylinder Executives’ standard fare, the single-variant V8 variant adds, as standard: 19x9.0-inch alloys with lower-profile 255/50 R19 run-flat tyres, rear air suspension, adaptive headlights with foglight-integrated turning lights (an $860 option on downstream variants), Bi-Xenon headlights with washers ($2110 etc), High-beam Assist $300), anti-dazzle/folding side mirrors ($650), four-zone climate-control ($3000), 12 HiFi speakers ($1200) and “Comfort” front seats with lumbar adjustment ($1900 for Executive sixes $4400 for base sixes).

Of course, there’s extra performance too, courtesy of the new 5 and 7 Series-sourced 4.9-litre 32-valve V8 that delivers 261kW at 6300rpm and 475Nm of torque at 3400rpm. BMW says the 4.8i returns combined EU fuel consumption of 12.5L/100km and 0-100km/h acceleration in 6.5 seconds. Top speed is also better, at 240km/h.

The array of optional X5 extras also includes head-up display ($2600), a panoramic glass sunroof ($3500), a heated steering wheel ($470), a sports steering wheel ($250), rear DVD system ($4000), rear side sunshades ($450), ski-bag ($500), heated front seats ($800), heated rear seats ($800), alloy side steps ($650) and, amazingly, metallic paint ($1700).