When we reviewed the BMW M135i, it's fair to say that we were blown away by its spectrum of all round talents. Its turn of speed had us suggesting that, should you really feel the need to go faster, you'd need to jump into a supercar.Yet here we are, just a couple of weeks later, driving another performance hatchback that is capable of blowing the M135i into the weeds.The Mercedes AMG performance division holds the giant's club of the performance hatch\/saloon world. Its products - which we've gained plenty of exposure to over the past few months - don't so much as demolish a road, as club it into sheer submission.And so it proves with this, the littlest performance AMG model. Based on the new A-Class, about which we have a good few reservations, the A45 has been heavily modified over its lesser brothers.It's got four-wheel drive for a start. Something you might argue it needs to put down its 360 horsepower. It wasn't long ago that this kind of bhp figure meant you were driving a Ferrari. Now it's available in the body style of a shopping car Merc.All of which would stand for nought if the A45 didn't actually drive well. Luckily, it does. In fact it goes down the road extremely well. The speed - in any gear, at any revs - just warps the mind. You are nearly always travelling 20 miles an hour faster than you think. Overtakes have occurred before your brain has had chance to process such information. Not for a long time have we driven a car in which you arrive at a junction, clock a car coming and just think "I'm going anyway" and pull out - time and again - with space to spare.Aiding and abetting progress here is Merc's 7-speed DCT gearbox. In sport mode it produces hilarious, almost "flat shift" style race-car upshifts, with an accompanying fart from the exhaust. It's fairly addictive to have it in this mode and add some aural amusement, because - incredibly - the A45's power comes from a humble 2-litre turbo four-cylinder engine. Which means that its weakest aspect is how it sounds. It might have the BMW whooped in the power stakes, but we'd rather listen to the Beemer's straight six all day, thanks.READ: BMW M135i reviewWhere the A45 perhaps scores best - at least beyond its crazy ground-covering speed - is in the cabin. It's not the very best cabin out there, but it's been improved to the point where it feels pretty special. You can decide whether the red stripes and carbon finishers are tasteful or tacky. But the sports seats and steering wheel, together with the paddles, have to go down as one of the best sit\/touch\/feel set-ups we can remember in any car.The seats - with their big wing backs - feel like true race seats which hold you firm without any of the discomfort for bigger frames that many sports cars seem to require as a compromise.The steering wheel - covered in Alcantara and Nappa leather - is just one of the best wheels we've ever used. But it is a \u00a3570 option... And a box you must tick. One of the reasons it perhaps feels so good is that the steering rack it's attached to is also great; the steering's weighted just so and - while it's not that "talkative" - it gives you great confidence in placing the car and knowing how it's going to react. In this regard, the A45 again has the M135i covered.Handling-wise, the A45 will inspire confidence in all conditions. We drove it fairly hard on a sunny day and it felt neutral - neither under nor oversteering. We're sure it can be made to go sideways if that's your thing and you're brutal enough with it, but we're just as sure that it's not as easy to do or as possible at low speeds as in the M135i.Credit to Merc's chassis engineers too. We thought the A45 would ride like a lump, but it actually coped with British B-roads pretty well.There's stacks of room to load up on Merc's best technologies, so you won't be punished for buying the smallest car in the range here. Yet all the toys and tinsel contributed to a rather frightening options list on our car. Taking an already wince-inducing base price of \u00a337,845 up to a "how much?" \u00a351,245.Which extras do you need? The steering wheel for starters. But definitely not the lane-tracking package and certainly not the four-grand's worth of carbon fibre detailing that had been daubed on to our review car. But you would want the bi-xenon headlights (mean as a \u00a3570 option at this level) and we'd still always tick the COMAND multimedia box for the upgraded Nav, SD Card slot, 10GB storage and the like - despite its stiff \u00a32,100 cover price.All of which leaves you with a \u00a339,000 base package that's more like \u00a345,000 once you're done. Which is about \u00a310,000 more than a correctly specced M135i. We can't get out of our heads that this is a simply vast amount of money for an A-Class. But this isn't just an A-class, it has been comprehensively re-engineered and is an utter weapon in which - come rain or shine - you will be able to outrun just about anything else on the road.Looked at that way, it's a bargain. What we're not sure about is whether that near-\u00a38,000 price difference over the BMW is really worth it. We would like to point out, too, that \u00a345,000 buys you all manner of exotic used machinery (Audi R8, Porsche 911, Aston Martin Vantage anyone?), but for people who want to go fast discreetly, and potentially with two kids in the back, there is little to compete with an A45.We'll be reviewing the A45 in full later in the year, to give a more definitive viewpoint. For now, if you're in the market for one of these mega hatches and your budget's got some elasticity, make sure you try an A45. It's worth it, just to hold that steering wheel.