Audi is on a roll, according to new boss Martin Winterkorn. But he sees room for improvement. More power and more character of course, but with costs kept down with a strategic alliance between Audi, Seat and Lamborghini - the sister brands in VW's 'sporty' division.

Ingolstadt engineers are working on three high-performance models: the new A4 coupe (with a V8 engine) due later next year; an alloy-bodied mid-engined V10 coupe for 2004; and the replacement for the TT coupe (2005) and the TT roadster (2006).

This time the Audi TT goes high-tech, rather than being a Golf clone. It gets four seats, a V6 motor and an aluminium chassis. Audi's key move is to tie up with Seat to build over half a million compact sports cars on the same basic platform.

First into the showroom will be the next Audi TT coupe (during the third quarter of 2005). The Seat version arrives in the second quarter of 2005. Following will be the drop-top versions, with Seat in the first quarter of 2006 and Audi in the second.

The switch to an aluminium body means the shells will be built in Audi's Neckarsulm plant. By splicing Seat into the project and pushing up volumes of the four models, Audi reckons Seat can afford to make the leap to all-aluminium production at a cost of just 500 Euros per unit more than a similar steel-bodied car.

While length, width and wheelbase are common to all four variants, Seat gets unique exterior panels and a slightly less plush interior. Sources say the Audi gets the new Jag S-type style upright grille.

The platform and chassis are in principle identical with the next-generation Golf family - featuring a new Focus-style four-link rear suspension. The most powerful models get four-wheel drive and a six-speed transmission. The V6 engine and twin-clutch gearbox will again be offered. The 3.2-litre V6 should be available in three strengths - a 240bhp TT, a 280bhp TT-S and a turbo 350bhp TT-RS. At the bottom end of the range there will be a new 150bhp 2.0-litre FSI and a 180bhp turbo. Seat is unlikely to get the V6 because it's priced against the Mazda MX-5. The TT moves closer to the BMW Z4 and the Porsche Boxster. But what of bigger shock moves from Audi? The first is a GT racer based on the V10 coupe - and then a top-secret engine for a mystery F1 team.