HIGH performance variants of the new BMW X5 and X6 will be joining the line up when it is released in the spring.

The Bavarian car maker has announced that the X5 and X6 M Competition models will be powered by a new 4.4-litre V8 engine fitted with 48 volt hybrid technology and will be priced from £123,350 and £126,050 respectively.

The engine develops 625hp giving the cars 0 to 62mph acceleration times of 3.9 seconds and top speeds limited to 155mph.

Best emission are said to be 291g/km for the X5 M Competition and 287 for the X6 model with official fuel economy up to 21.9 and 22.2mpg.

Both versions are fitted with BMW's adaptive suspension specifically tuned for M models, all-wheel-drive and active rear differentials.

The two cars will join the new X5 and X6 ranges which are due to be released in April and the 48V technology is making its debut on the brand's high performance models.

The system uses an electric motor and power electronics integrated into the housing of the eight-speed M Steptronic transmission where it delivers an additional 12hp and 200Nm of torque.

The energy required is stored in a 48V battery in the engine compartment, charged through adaptive recuperation under braking and overrun.

The electric motor also acts as a starter generator; after pausing at junctions or in traffic congestion, the 48V generator restarts the V8 engine quickly and unobtrusively.

The new V8 engine delivers peak torque of 750Nm between 1,800 and 5,800rpm and generates maximum output of 625hp at 6,000rpm.

As such BMW says the X5 M Competition and BMW X6 M Competition can reach reach 124mph in 13.8 and 13.6 seconds respectively.

The new BMW X5 M Competition and BMW X6 M Competition sprint from 50 - 75mph in 3.2 seconds in fourth gear and 4.2 seconds in fifth for the X6.

The maximum speed can be raised to 180mph with the fitting of an optional M Driver's Pack.

Both Competition versions feature the same styling revisions being made to the new X5 and X6 including a sleeker looking nose but come with specific M styling tweaks such as large, wide open air vents in the front bumper and specific M Competition rear light clusters.

The new X5 and X6 are priced from £66,230 and £72,430 respectively.