BMW is planning to introduce a new BMW X6 within the next 18 months in direct response to a raft of similarly conceived four-wheel-drives already confirmed by rivals such as Audi, Land Rover and Mercedes-Benz.

Sister car to the third-generation X5, the second-gen X6 forms an integral part of an expanded range of sporting four-wheel-drive models currently under development at BMW’s engineering headquarters in Munich.

Joining the high-riding luxury SUV in the German car maker’s burgeoning line-up from the middle of the decade will be the smaller but more affordable X2 and X4 models ― a move that is set to bolster BMW’s number of dedicated four-wheel-drive models from four today to six by 2016.

The new X6 is set to adopt an even more aggressive appearance than that of today’s model, which has proven popular in markets such as China, North America and Russia.

BMW design sources have indicated to Autocar that the new model will move further away from the X5 not only in shape but also in detailing. One source said: “We want to give our sporting models a more individual look, separating them more visually from the more practical models in our line-up.”

A marginal rise in length ― from today’s 4877mm to about 4910mm ― is aimed at providing the new X6 with added levels of interior space, something that BMW sources identify as a weak point with the first-generation model, which has been on sale in the UK since 2009. The overall packaging is also helped by the adoption of a reconfigured chassis with a longer wheelbase and wider tracks.

The new X6 is based around a shortened version of the newly engineered monocoque platform found beneath the next X5, which is due for UK launch later this year. Described by insiders as being more sophisticated than that used by the first-generation X6, the composite steel structure is claimed to bring significant weight savingsdue to the use of a higher percentage of hot-formed high-strength alloys.

More weight saving has been achieved through the adoption of new axle assemblies, which are said to be shared with the 5-series. Unlike today’s model, which receives a mechanical torque-vectoring system, the new one is set to adopt an electronic system in a move that, insiders suggest, brings further weight reductions.

Lower-end models will ride on steel springs while top-end X6s will continue with self-levelling air suspension. The dampers will offer three levels of stiffness, with hydraulically operated anti-roll bars set to be made available as an option.

Further developments include a state-of-the-art electronics platform that forms the basis of a new ‘FlexRay’ system that, Autocar can reveal, will provide the scope for electronic upgrades during the life of the car by allowing the central processing unit to be easily upgraded.

The new electronics platform not only enables electronic chassis upgrades to be undertaken but also ensures that the new X6’s various multimedia systems can be updated when new software packages become available.

Power for the new X6 will come from a range of new or upgraded twin-scroll turbocharged 3.0-litre petrol, sequential twin-turbocharged 3.0-litre diesel and tri-turbocharged 3.0-litre six-cylinder engines, as well as revised twin-turbocharged 4.4-litre V8 petrol units in both standard and M division guises. All will benefit from incremental increases in power over today’s units and be mated to a standard eight-speed automatic gearbox.

Also under development is a plug-in X6 ActiveHybrid, which combines the twin-scroll turbocharged 3.0-litre six-cylinder petrol engine with an electric motor mounted within the gearbox housing and a lithium ion battery sited within the floor of the boot.