There have been so many details coming out about the new Audi A7 that when it finally gets unveiled we are more than likely to know everything about it already. But Audi will only have themselves to blame due to a series of leaked documents including their 2010 engine product offensive and roll out schedule until 2012, now a new leaked document has been obtained by autoweek revealing new details for the new Audi four-door coupe.

Audi will be producing both a hard-top and soft-top convertible versions of the A7 – making Audi the first premium automaker to produce a modern day four-door convertible. Although producing this model variant will be an engineering nightmare.

Following the coupe and convertible versions will be the high-spec S7 and super-spec RS7, the later is set to be powered by a tuned version of the RS6's twin-turbocharged 5.2-liter V10 engine with a power output of around 600hp and will feature a new torque-vectoring system.

The A7 will offer a choice of two direct injection engines starting with a 204-hp naturally aspirated 2.8-liter as well as a 300hp 3.0-liter supercharged engine – the same engine that is set to be used in the Audi A6 facelift and new S4. The 394-hp turbocharged 4.0-liter V8 has been saved for the S7 which will be launched in November 2010.

Audi are also developing a new hybrid-drive system which is primarily expected for the Audi Q5, but Autoweek says the A7 is set to benefit from the lithium-ion battery technology as well.

The Audi A7 is part of the German automaker's aggressive product strategy which will see the current 23 model lineup expanded to 40, targeting a 50% increase in sales by 2015.

Audi continues to underscore the importance of the US market to its future fortunes with two world debuts at the Detroit Auto Show. In addition to the R8 V10 that we saw last month, we got our first look at the Sportback concept. The Sportback is a preview of the A7 sedan due to arrive in the next year or so. As expected, this is Audi's take on the four door coupe/sedan idiom. Compared to the Porsche Panamera, this is one actually works. It takes the look we've come to expect from Audi and updates it with slightly sharper lines and a reshaped grille, along with even more LED lighting.

The Sportback name refers to the fastback roofline and Audi boss Rupert Stadler made it clear that the new look will become a common trait in the Audi lineup, beginning with a new A5 Sportback coming later this year. Under the hood, the Sportback gets a 3.0-liter TDI diesel V6 with 225 hp/406 lb-ft paired up with a seven-speed S-Tronic dual clutch gea box. The whole thing is topped off with automatic start stop to give a combined 39 mpg (US). Based on these specs we can't wait for the A7 to arrive.

Hit the jump for the press release and a 20-second video walk-around of the Audi Sportback concept.