This morning I’m at a small test track around 50km outside Stuttgart for an Audi technical presentation on the advances the company is making in lightweight design.

Unexpectedly, one of the test cars is the technology mule for the Quattro concept that Audi unveiled last year. It may look like an ordinary A5 coupe, but it’s actually built around a bespoke aluminium spaceframe chassis, with an aluminium skin and carbon reinforced plastic bonnet and bootlid.

It uses a 400hp version of the TTRS’s five-pot engine, driving a 60/40 rear-biased quattro drivetrain through a six-speed manual ‘box. With the stock A5 coupe interior, this prototype weighs in at an impressive 1400kg. With a planned lightweight interior and the 150mm reduction in wheelbase used for the Quattro concept, that all-up weight could drop to just 1300kg.

This development car is part of the process of proving the Quattro concept ahead of it being given the green light by the Audi board and I’ve just stepped out of it after three quick and punchy laps of this small circuit.

This prototype is fast, fluid and extremely well-balanced. The performance, as you might expect, is vivid. The car did not betray the fact it has a longitudinal engine hanging out ahead of the front wheels, instead it felt utterly neutral and utterly unstickable. It is also glorious light, agile and enthusiastic.

Given a boot full out of bends, this mule had impressive lag-free pace, with a crisp and quick shift-action. Pushed around bends, the steering weight remained consistent and there wasn’t a hint of understeer. Overall, it flattered the driver and instilled confidence.

As it stands, this prototype is probably one of the best-handling Audis yet - at least on the basis of this short test drive. In production form, as the Quattro Concept, with a shorter wheelbase and another 100kgs shaved off the weight, it could well be the best handling Audi ever.

I’m sure of one thing, as soon as the Audi board members try this prototype, the Quattro concept will be heading for the showroom.