I like the look of that. What is it?

That is the Audi TT Clubsport Turbo Concept, created for this year's running of the annual Wörthersee festival in Austria.

Is it a road going version of the TT Cup Sport racer?

No, the Clubsport Turbo makes the racer look feeble. This one has 600hp...

Is it packing the V10 from the R8 or something?

No it 'packs' a turbocharged 2.5-litre five-cylinder engine with the boost wound way up.

Ah so it's like the old Mitsubishi Evo FQ-400 then. Loads of power but huge turbo lag?

Nope, the Clubsport will do 0-62mph in 3.6 seconds and be an entire car length ahead of its nearest rival in a mere 2.5 seconds according to its maker. You see, Audi anticipated the lag issue and fitted an electric turbocharger to compensate. So it has instantaneous power down low but still with the 600hp headline grabbing figure.

Ah the e-turbo. I thought that was only for Audi's diesel offerings?

This is the first time the technology has been used on Audi's TFSI petrol engine. The electric turbocharger is paired with a 48-volt lithium ion battery that harnesses power while the car is coasting.

Coasting? Battery systems like this usually harvest power under braking.

Not the Audi system. The stop-start function can kick in earlier as the power supplied by the 48-volt battery is enough to kick a moving motor back into life. So while you are coasting up to the traffic lights the engine is killed, 'free' power from the forward motion of the wheels are converted to electricity and the whole shebang is ready to assault the asphalt the moment the lights go green again.