Citroën is boosting the power of its diesel C5s while cutting CO2 emissions, as well as introducing a new turbo petrol model.
A 160bhp 2.0 HDi diesel has replaced both the 140bhp 2.0 HDi and the 173bhp 2.2 HDi engines, and compared with the 140bhp versions has reduced CO2 emissions from 153g/km to 147g/km in the saloon.
The Tourer version has also fallen by 6g/km but the cut from 155g/km to 149g/km means it is two BIK tax bands lower.
The new diesel produces 251lb-ft of torque at 2000rpm, and its fuel consumption of 50.4mpg for the saloon and 49.6mpg for the Tourer represents an improvement of three per cent.
The new petrol engine is a 155bhp 1.6-litre turbo that replaces the normally aspirated 143bhp 2.0-litre, and produces 177lb-ft of torque from 1400rpm.
Compared with the old 2.0-litre petrol engine, emissions are reduced from 198g/km to 167g/km for the saloon, while fuel economy in improved by 18 per cent.
Citroën has renamed the SX equipment grade VTR, although no changes in specification are made, while a new integrated Bluetooth system with USB socket are now standard on Exclusive models, allowing hands-free phonecalls and the ability to connect portable MP3 players directly into the car's audio system.