Alfa Romeo has finally begun to show us some of the substance behind its much-hyped revival plan. This is the Giulia Quadrifoglio, the top-end version of the new BMW 3-Series rival. They haven’t said much about the spec, but what they have said is pretty striking.

How about 503bhp for a start? Such M3-beating power is courtesy of a ‘Ferrari-inspired’ 3.0 V6 with two turbos for power and cylinder activation to improve economy when going more gently.

They did rev the motor for us, and it sounds absolutely amazing, gutteral and hard-edged and yet sweet. The 0-62 time, they say, is 3.9 seconds. That’s seriously quick.

Richard Hammond drives the Alfa 4C

Other than that, tech details are scant. Instead, Alfa gave us a lot of hyperbolic talk about the spirit of the car. CEO Harald Wester said rival cars are all the same these days. “Premium is a commodity, a sea of indifference.”

He says an Alfa should be distinct. “We said what if we started to actively drive? The new Alfa Romeos will put the driver centre stage, totally immersed in the act.”

The 510bhp car is rear-drive, amazingly, although 4WD will be optional elsewhere in the range. It has a proper torque-vectoring rear diff.

First drive: Alfa Romeo 4C Spider

There’s all-aluminium suspension with an extremely sophisticated double-wishbone ‘semi-virtual steering axis’ setup at the front. So they want it to handle. The steering is claimed to be more high-geared than any rival. That should mean a pointy nose.

Weight distribution is 50:50, and there’s a lot of effort to reduce that overall mass. Carbonfibre is used amazingly extensively: propshaft, roof, bonnet. Not only the suspension and subframes are rendered in aluminium, but the doors and wings too. Overall weight is about 1500kg, which is very tidy for a car of this kind.

Brakes are carbon ceramic. The body is said to generate downforce: at the front there’s an active splitter, while at the rear you’ve got a huge diffuser and four fat tailpipes - de rigueur hot-saloon tropes.

It’s also very distinctive-looking. There are elements of Maserati Ghibli in the massive rear haunches, and we gather (we’ll be investigating over the next hours) that there is some relationship under the skin.

But the Alfa has an aggressive neat and very animate face, with the trefoil air intakes a modernised version of the lovely 1950s Giulietta Sprint. The side forms are simple and organic.

That, of course, is the fast Giulia: how much of this virtual aggression will find its way to the mainstream versions of the car we don’t know. There will be turbo four-cylinder petrols of 1.4-litre and 1.8-litre capacities, and four-cylinder and V6 diesels.

The dash is a relatively simple shape, like the outside, with an elegant sweep for the top structure. The start button is on the steering wheel, and on the console is a big round version of Alfa’s ‘DNA’ mode switch. But this time is goes one louder, from ‘Dynamic’ to ‘Race’.

Alongside is a straightforward, circular controller than runs the infotainment screen. That apart, the cabin isn’t pebble-dashed with switches. That’s because the Giulia does without the vast array of electronic support systems the German rivals are touting these days.

The Giulia goes on sale in the UK in September 2016. Hold tight for more info. The unveiling today was a very tightly-controlled and info-light event in Milan; we will be gathering more over the next hours and will have updates soon.