What's all this about?

The 2014-introduced Mercedes GLA is due its midlife overhaul, so here is the revised car - and the biggest news is that the range-topping AMG variant has more horsepower, better fuel economy and quicker acceleration.

How has that come about?

Its 2.0-litre turbocharged four-cylinder engine has been boosted by 21hp and 25Nm to peak outputs of 381hp and 475Nm; the same change happened to its closely-related A 45 stablemate late in 2015. That trims the 0-62mph from 4.8- to 4.4 seconds, although the top speed is the usual 155mph limited, which can be optionally raised to 168mph with the AMG Driver's Package. Fuel economy creeps up from 37.7- to 38.2mpg as a result, while the CO₂ emissions rating is marginally reduced from 175- to 172g/km.

What's the black-and-yellow GLA 45 in the pictures?

That's the Yellow Night Edition, which comes in either Night or Cosmos Black with a load of Graphite Grey and yellow detailing - such as the yellow-pinstriped black alloys, or the yellow patches on the sides of the rear spoiler, or the yellow fillets lower down the car. Inside is a similarly yellow and black sports interior, although you can just have a 'regular' GLA 45 that comes with a red and black finish instead (silver and black is optional). The Yellow Night Edition also gets the Aerodynamics package, the Night package, the Light and Sight package, performance seats with a memory function plus and a yellow 12 o'clock mark on the steering wheel (which also benefits from silver chrome trim and AMG Edition badging) as standard.

OK, so what has Mercedes done to the regular GLAs?

Subtle tweaking of its bumpers, headlight clusters and rear roof spoiler, making it ever-so-slightly more aerodynamic at 0.28Cd, compared to 0.29Cd for the pre-facelift cars. New upholstery, trim panels, redesigned dials in the instrument cluster and chrome-finish surrounds for many of the major controls are also added, while as an option on all GLAs you can have a 360-degree camera system.

So there are no new engines here?

Well, there is a 184hp GLA 220 4Matic added to the line-up... but only in continental Europe. We won't be getting that particular drivetrain arrangement here in the UK.

Fair enough. How much and when does it go on sale?

UK prices and specifications will be confirmed imminently, as the car goes on sale on January 9 following its debut at the North American International Auto Show (NAIAS) in Detroit. First customer cars will therefore be delivered in April 2017.

Matt Robinson - 9 Jan 2017