Not content with launching the spicy TT S, Audi is now turning its attention to a fiery RS version of its evergreen coupé and roadster.

Our spies caught the new TT RS out on test with remarkably little disguise to hide its identity.Audi will pitch this car as a latterday successor to the Ur Quattro – Ingolstadt’s 1980 rally original. It’s easy to see why. 

The marketing suits are confident the uber-TT will be fast enough to warrant comparison with the rally legend: it will have a warbling five-cylinder engine and, naturally, it will pack four-wheel drive.

The RS will become the first TT to have five, rather than four or six, cylinders.

The engine comes from the further reaches of the Volkswagen Group parts-sharing cupboard – it’s more normally seen under the bonnet of a US-market VW Jetta.

We’ll see the RS in the metal at the 2009 Geneva Motor Show, with UK sales pencilled in for next July.

Our spyshots have captured both coupé and roadster variants, a strategy confirmed by our sources at Audi.

The 2.5-litre five-pot will be turbocharged to crank out some 340bhp, spelling a restricted top speed of 155mph and a 0-60mph time knocking on the door of five seconds flat.

Make no mistake, this will be very nearly as fast as Audi’s R8 supercar – yet for roughly half the price, at an estimated £40,000.