The new Mercedes A45 AMG brings a whole new level of mad to the hot hatch concept. You get 355bhp and 332lb ft of torque, which earns the engine the title of most powerful four-cylinder 2.0-litre turbo ever in series production plus, this is the first time the AMG badge has graced anything smaller than a C-Class.
With on-demand four-wheel-drive traction and a seven-speed dual-clutch automatic gearbox as standard, the A45's closest rival is the Audi S3, but it will also compete with the rear-wheel-drive BMW M135i.
Obviously it's quick, but the more pertinent question is whether the A45 AMG can justify its price and overcome some of the dynamic shortcomings in particular the wooden ride that blight the standard A-Class.
What's the 2013 Mercedes A45 AMG like to drive?
It's good fun, and yet it also has an edge of maturity to it that's crucial in a car of this price. Power arrives courtesy of a single large turbocharger, but between the seven-speed auto, sharp throttle response and the engine's broad mid-range, the A45 is actually a flexible performer. Thrilling, but not scary.
The gearbox offers three settings, but none of these is perfect. Even in the Sport setting it occasionally hangs on to ratios for too long in normal road driving, while in manual mode it's too reluctant to change down as you approach corners.
Even so, this is a great powertrain that's particularly entertaining when paired with the optional sports exhaust, which emits a raucous, machine-gun like explosion of noise on upshifts when you're accelerating hard.
The accessibility of the performance has as much to do with the four-wheel-drive system as anything else. In standard conditions, all the power goes to front wheels, but when circumstance demands, power is shuffled between the fronts and the rears.
The A45 can also brake an inside wheel to aid cornering stability. The result is that the baby AMG sticks rigidly to the road and will go precisely where you want it even in seriously quick corners, and there's little body roll or loss of traction to corrupt the neutral handling.
Only under very hard use such as track driving will it start to struggle for traction and wash wide in corners.
Elsewhere, even sharp direction changes or varying throttle inputs don't unsettle the car, while the steering is quick and pleasingly natural without being too neurotic in normal driving.
The A45's uprated suspension also impresses. It hasn't simply been lowered; the front set-up now has revised components, while the rear is completely different from that in the standard A-Class.
The anti-roll bars are larger, and the shock absorbers and springs also have a bespoke arrangement. The resulting ride is certainly firm, particularly over bigger bumps, but it copes well with eroded surfaces and offers enough pliancy to make it acceptable by hot hatch standards. In fact, the A45 is more comfortable over many road surfaces than lesser A-Class models.
What's the 2013 Mercedes A45 AMG like inside?
As you'd expect, the car's styling upgrades have made it to the interior, too. A carbonfibre-effect dashboard is standard, as are red vent surrounds and stitching, while the electrically adjustable leather sports seats offer good lumbar support, and the deep bolsters hold you firm in hard cornering.
The A45 does feel classy and special inside, although inevitably it still suffers from many of the flaws of the standard model, including a narrow boot opening and slightly awkward entry to the rear seats. At least cabin space is on a par with that offered by most rivals.
Climate control, DAB radio, USB input and the Comand 5.8-inch colour screen are standard, although it's disappointing that sat-nav is an option on a car of this price and prestige.
Should I buy one?
The A45 AMG is a stonking thing to drive in the right circumstances, and while it's far from cheap, some buyers will see the four-wheel drive, automatic gearbox and superior pace as justification enough for the 7000 premium you'll pay over a manual BMW M135i.
However, we think the BMW is a better buy; it might not be quite as fast in a straight line, but it's more fun to drive in most situations and easier to live with the rest of the time. The fact that it's also much cheaper only extends its advantage.
What Car? says...
Engine size 2.0-litre turbo petrol
Price from 37,845
Torque 332lb ft
0-62mph 4.6 seconds
Top speed 155 mph
Fuel economy 40.9mpg
By Vicky Parrott and By Will Nightingale