Mercedes-Benz A200 vs Mercedes-Benz CLA250

What's the difference?

Meet the world’s most aerodynamically efficient passenger car. Mercedes-Benz says the drag co-efficient for this new sedan version of its fourth-generation A-Class is the lowest ever measured for a passenger vehicle.

Which is quite a claim, but you only have to look at it to see how much work has gone into marrying good looks with slippery aero performance.

The A-Class sedan is substantially longer and fractionally taller than its hatchback sibling, but does that mean it’s better, or simply different?

If you're after a hot hatch with a boot, you can't have one because it wouldn't be a hatch anymore.

What you can have is this little beast - the new, second-generation Mercedes-AMG CLA 45 S, a small coupe-style sedan sharing its high-performance DNA with the hot as bubbling lava A 45 S hatch.

Packing 300kW – that's just over 420hp – and 500Nm its 2.0-litre engine is claimed to be the most powerful series production turbo four ever made.

And Australian deliveries are scheduled for early 2020, with a likely price tag in the mid-$90k bracket.

Mercedes-AMG invited us to the car's global launch in Madrid, Spain, where we got behind the wheel on road and track.