WHETHER it's the 78-Series TroopCarrier wagon offering up to 11 seats, the 79-Series cab-chassis with payload to burn or the more civilised 100-Series coil-sprung wagon, Toyota's full-size LandCruiser has carved a reputation as the vehicle of choice for the Aussie Outback, for both work and play.

The downsized Prado wagon extended that appeal to family types in 1997, when the original "son-of-LandCruiser" went on sale, offering all of the Cruiser 100's off-road ability and full-chassis durability in a more compact body that still housed up to eight seats.

More evolution than revolution, the second-generation Prado of 2003 didn't mess with the tried-and-proven formula but added a bigger new 4.0-litre V6 and funkier styling.

Australians continued to flock to Prado and it took Ford's clever Falcon-based Territory SUV to knock Prado off its long-held perch of Australia's most popular medium SUV in 2004. But we're still the second-biggest Prado market outside Europe.

Subtle running refinements, including six-speed manual and five-speed auto transmissions for V6 variants, have kept Prado MkII relatively fresh since then, but now the same transmissions are available with an all-new HiLux-sourced turbo-diesel, alongside a host of minor equipment upgrades across the range.

Of course, the new-generation diesel is the biggest news here, and transforms the oil-burning Prado from a leisurely truckster into a far more civilised and willing performer.

Yes, the huge advance in cabin quietness (which is also aided by extra dashboard noise supression measures) and general vibration and harshness levels is the most striking aspect of the upgraded diesel.

But the new manual and automatic transmissions also make it easier to capitalise on the new engine's considerable extra urge right across the rev range.

Undoubtedly, a "proper" four-wheel drive with a gross vehicle mass of 2800kg could never be called spirited, and it takes significantly extra urge to make a discernible performance difference in a vehicle of this bulk.

But with 410Nm of torque now on tap from just 1600rpm (versus the old engine's 343Nm at 2000rpm - up 19.5 per cent), the upgraded turbo-diesel Prado is far closer to the likes of Mitsubishi's lighter Pajero in terms of tractability and open-road performance.

Improved throttle response and smoother running across the board (not to mention the 80 per cent of peak torque available from idle) heighten the impression of more rapid acceleration, and the extra top-end power clout (127kW from 3400rpm instead of 96kW at 3600rpm - up a big 32 per cent) also brings Prado diesel closer to Prado petrol in terms of outright acceleration.

Significantly reduced fuel consumption and exhaust emissions are simply icing on the cake.

Toyota now claims official fuel consumption of less than 10L/100km for both manual and auto Prado diesel variants, with the (six-speed, up from five-speed) manual dropping 19.3 per cent (or 2.2L/100km) to 9.2L/100km and the (five-speed, up from four-speed) auto dropping a massive 26.2 per cent (or 3.3L/100km) to 9.3L/100km.

And while it should be pointed out that a stricter new emissions requirement for 2007 is the primary reason HiLux's newer diesel now sees duty in Prado (whose V6 petrol engine is unchanged), Toyota has also seen fit to add some worthwhile additions to all Prado equipment lists.

Thankfully, there's no change to Prado's full-time 4WD system with low-range reduction ratio, but the entry-level GX gets wider steels wheels and tyres, wider side steps and guards, body-coloured bumpers and door-handles and a chromed grille and mirrors.

Alas, ABS brakes and cruise control remain optional for the base Prado (as part of a $1250 pack), and the least expensive Prado now costs $3100 extra ($47,290). Of the 300 GX sales Toyota expects every month, most should go to fleets.

The new pricing structure sees the diesel command a $1000 premium over the petrol and auto variants priced $3000 above manual variants.

The GXL also adds worthhile extras standard, including privacy glass and roof rails, while the stability control and curtain airbag-equipped VX now gets power-operated front seats, leather seat trim and leather/woodgrain door trim.

A Lexus-style Optitron instrument cluster with added warning features is the only upgrade for the Grande flagship, which continues to add rear air suspension, sat-nav and a sunroof as standard. Grande pricing rises to more than $75,000 for the diesel.

While that maintains Prado's position as the most expensive non-European medium SUV available, a superb new diesel will only increase its reputation as the unbreakable, go-anywhere family 4WD of choice for Australians.