Audi to take on Porsche? Surely not...
Yes, Porsche and Audi have struck a deal that will see them join forces to jointly develop the R4 – Audi’s entry-level sports coupe and roadster – and the next generation Boxster/Cayman. Audi’s plan is to have a four-strong line-up of R-cars: an R10 super coupe (based on the Le Mans-winning diesel-powered racer), the next generation R8 (complete with roadster version), an R6 to sit between the Porsche 911 and Boxster, and then the entry-level R4, a mid-engined two-seater strategically aimed at the £28-35,000 price bracket.

The obvious sister model of the R4 is the next-generation Boxster/Cayman, known internally as project 981/C8. Due in 2011, the Mk2 roadster and coupe will of course be rear-wheel drive and fitted with six-cylinder boxer engines. That's in stark mechanical contrast with the proposed Audi spin-off, which will run forced-induction four- and five-cylinder engines through advanced low-friction quattro four-wheel drive with torque vectoring.

So the R4 will get boxer engines and the Boxster will get quattro all-wheel drive?
Not quite. Hooking up with Porsche has some key advantages for both parties. Apart from sharing the huge development costs, Porsche gets its hands on Audi’s aluminium spaceframe bodies, powerful diesel engines, lightweight low-friction four-wheel drive with torque vectoring and dual-clutch transmissions for almost all torque classes. Audi in return gets to tap deep into Porsche’s first class engineering base and its peerless financial ability that constantly puts it at the top of the profitability tree.

Our sources indicate that Audi has earmarked the 300bhp turbocharged four-pot – as seen in the TT Clubsport Concept (above) – and the blown 350bhp 2.5-litre five-cylinder unit (currently being prepped for the hot SR version of the TT) for the R4. Although Porsche could adapt the new four-wheel drive system which is being developed for the 997 replacement – codenamed 991 – for the next Boxster/Cayman, it’s unlikely given the associated weight penalty of the drivetrain. But Audi will want to play its quattro trump card, so expect its engineers to heavily modify the 991’s all-paw layout for the R4.

Are we talking identical twins here?
Far from it. Basic chassis architecture aside, the two cars will also share a second-generation dual-clutch transmission, all the latest driver assistance systems plus night vision, a head-up display, brake energy recuperation and trick suspension set-ups with MagnaRide from Audi, and PDC from Porsche.

Don't worry though, the Boxster and R4 won't look the same. With its rear-wheel drive layout and aluminium doors and roof, the Boxster/Cayman will be lighter than the R4 coupe and roadster, with associated ride, handling and economy advantages. And with Michael Mauer at Porsche and Wolfgang Egger at Audi – two of the most ambitious young designers in the industry – going head to head to prove their worth, expect both cars to be distinctly different in appearance.

A marriage made in automotive heaven, then?
It all sounds like the perfect match, but yes, there are some major political obstacles to negotiate first. Timing is still a major bone of contention – Porsche has its plate full until 2012 when the next Cayman rolls off the line. But Audi wants to launch its R4 as soon as 2010 – one year after the Panamera, one year before the new 911 and on a collision course with the follow-up to the Cayenne, not to mention the Cayman facelift.

As a result, the whole issue is fast becoming quite political, and the fact that there are simultaneously about a dozen other promising cooperation projects under evaluation does not necessarily help the case. But the general direction is pretty clear. In a nutshell, Porsche will – as the new master of the house – make sure that neither Audi, Lamborghini nor Bugatti does anything to threaten its unrivalled 16 percent profit margin.

So who is calling the shots here?
There’s no doubt that the three key players in this deal – Ferdinand Piech, Wendelin Wiedeking and Martin Winterkorn – will face one challenge after the other as they tread the line between optimum market coverage and minimum cannibalisation in coordinating the future model mix of Porsche and Audi (not to mention Lamborghini, Bugatti and Bentley), trying to stay true to the brands and to stagger the offerings in a way that is complementary within the group and aggressive in relation to the competition.

If they get this right the rewards will be huge – the perfect incentive to work together again on the next tie-up between the Q5, Audi’s mid-sized sports utility, and Porsche’s proposed Cayenne-lite that will sit below the current Cayenne (above).