Thankfully, Car thought it was a good idea to post some background on their website about how the images were created and how certain information was attained. Unfortunately, if you want all the details you have to trek on over to your local newsstand, but a few things are worth noting from both the article and a thread on M3post.com.
To begin with, the car in the picture is a 335i that was photochopped with insider information that gave up the rear styling, gills, side skirts, spoiler and wheels. However, beyond the exterior styling, technical information is scarce. At least online.
Additionally, one forum member at M3post got word that a concept will likely bow in Geneva, similar to the M5 concept before it.
We're going to head on over to our local bookseller to get all the techy details, including power output, transmission specs and the surely-drool inducing redline.
[Sources: Car, M3post via Jalopnik]