BMW has refreshed its 5 Series line-up with the arrival of two new V8-engined models – the 540i and 550i – which slot in between the six-cylinder 5 Series models (525i and 530i) and the range-topping 373kW V10-engined M5.

Available now and priced from $135,500, the 540i uses a 4.0-litre V8 that develops 225kW and 390Nm. In turn, the $162,400 550i uses a 4.8-litre V8, which produces 270kW and 490Nm and replaces the previous 4.4-litre engine found in the 545i.

Both are mated to a six-speed Steptronic automatic transmission.

Compared with the six-cylinder 530i, the 540i gains the following: chrome exhaust extensions, alarm, lumbar support, headlight washer system, adaptive HID headlights, 18-inch Star-spoke light alloys, navigation system, TV, voice recognition and high-beam assist.

The 550i adds a heads-up display to this extensive list, while both new 5 Series variants feature the redesigned iDrive Controller and a start/stop button on the instrument panel.

The latest generation DSC+ is now standard across the 5 Series range, including Hill Start Assist, a Brake Standby function, Brake Drying function, Brake Fade Compensation and Comfort Stop features.

Bluetooth mobile phone preparation will become standard on 2006 525i, 530i Touring, 530i and 530d models, in addition to a 10 speaker Hi Fi system on 530i, 530d and 530i Touring models.

In addition, with the inclusion of new start-stop buttons for 5 Series, Comfort Access becomes available as an option across the model range.