Vauxhall is offering new Omega buyers the opportunity to take a 2.5 litre V6-engined CD or top-of-the-range CDX model for the same price as the equivalent 2.2 16v model.

The saving is up to £1400.

"This is a one-off chance for a potential Omega owner to add some great power under the bonnet of Omega - for no extra outlay," said Steve Bryant, Vauxhall's Omega product manager. The offer begins on 3 August.

The 2.5 litre 24v ECOTEC engine turns in a maximum power of 170PS (125kW) at 6000rpm, and top torque of 227 Nm (167.4 lb.ft). Maximum speed in manual gearbox form is 142mph.

The alternative 2.2 litre 16v ECOTEC engine returns 144PS (106 kW) at 5400rpm with maximum torque of 205 Nm (151.2 lb.ft) at 4000 rpm. Top speed: 130mph.

Vauxhall has for some time offered 1.8 litre and 2.0 litre petrol engines in its Vectra range for the same price.