Road Test: Mercedes-Benz C Class C250 D Elegance 4dr Auto

Mercedes is an expert at the blink-and-you'll-miss-it facelift. You're not going to miss this, though - the C-Class's mid-life surgery has transformed the compact executive saloon. With typical Teutonic attention to detail, Mercedes claims 2,000 parts have been changed.

The update brings the car in line with the rest of the Merc range's looks. It's worked, too. We parked up next to an old C-Class, and the new one is much sharper, and visually has more in common with the E-Class and S-Class.

The interior has also been upgraded - if you spec leather (£995), there's more of it on the doors, the old flip-out satnav is now a smarter integrated unit and the dash buttons are more modern. The old C-Class wasn't especially dated or downmarket inside, but this car looks and feels more prestigious, more worthy of the badge and simply a nicer place to spend time.

We certainly haven't ticked off all 2,000 changes yet, though. Every single engine, including the V6s, has start/stop, and the big-selling four-cylinder diesels are available for the first time with an optional 7spd automatic. Mercedes is proud of this gearbox (which will make up 80 per cent of all C-Class sales), because in the diesel engines it's as efficient as the manual - chiefly thanks to a long seventh gear.

The figures vary depending on trim and engine choice, but our C250 CDI Elegance emits only 131g/km while returning a mighty 58.9mpg - regardless of whether you spec the six-speed manual or the £1,500 auto. That's impressive, but not quite as all-conquering as Mercedes would like you to think. BMW claims the eight-speed auto being dropped into 2012's new 3-Series will return better figures than the manual.

Nevertheless, the face-lifted C-Class largely offers an interesting alternative to the 3-Series. The start/stop works brilliantly because it fires up so quickly (even on the autos), and the 250 CDI - with 201bhp and 369lb ft - has plenty of punch, so munching motorways and picking off slow-moving traffic is easy. The suspension has been wisely left alone, as the C-Class has always driven rather nicely, but combining that with the posher interior means the C is starting to feel like a mini S-Class.

But, and it's a big but, the engine is too rough. For a £30,000 car, and especially one with a Mercedes badge, there's way too much diesel rattle. It doesn't gel with the C-Class's relaxed, upmarket ambience.
 This is a pity. The latest C-Class is no sports saloon, but it is smart and effortless. Until the refinement is improved, though, the BMW 3-Series is still king.