The Mercedes S 320 CDi has few flaws as a luxury saloon. Even one of those can’t be entirely be blamed on Stuttgart burghers, but rather the vagaries of the British company car tax system, which saddles any diesel not Euro 4 emission-compliant with a three per cent tax penalty. But that’s now been redressed with a clean-up for the 3.2-litre six-cylinder turbodiesel, courtesy of a particulate filter.
There are some drawbacks to going greener, though. Extra-urban economy figures drop slightly, though improvements to urban fuel sipping make the overall figure unchanged at 35.8mpg. More important, CO2 emissions actually rise from 204g/km to 209.
The tax burden will be the main interest to buyers, though, and without that three per cent bundled on it’s good news if a chunk of your salary is spirited away each month. If you’re a 40 per cent tax payer – and let’s be honest if you’re an S-class driver you will be – the latest version will set you back £459 per month, compared to the £493 you might have been contributing to Mr Brown in the dirtier diesel.