At the end of this piece from Racecar Engineering there ia a link to see photos of the rear ends of most of this years cars. Interesting that already Macca and RBR are running quite different styles of double diffusser, we'll have to wait a bit to see if it results in any big performance differences.
The 'double deck diffuser' was a source of great controversy last season and the concept arguably decided the world championship in Brawn's favour. This year the devices are back and every team has started off with the design in mind.
There have already been questions surrounding the legality of some cars, but as Williams Technical Director Sam Micheal explains, the furore of '09 is not likely to be repeated; "I would be amazed if there were any further rows over the diffusers, because once you have a ruling on an interpretation the limit of that interpretation has not bounds, it is basically down to what the teams can come up with. It is very different to having a different interpretation. I haven't seen anything on the cars yet that is a different interpretation, there are lots of extremes of the interpretation but nothing new."
However Red Bull's Adrian Newey was more cautious on the same topic "in the case of the McLaren and Renault they have huge outlets wich means that logically there are huge inlets. But until they are kind enough to hang their car in the air it is hard to tell exactly what the details are. I imagine that they are doing something different and I think I know what it would be but without seeing it it is pretty hard to tell. McLaren and Renault started early on with the concept of theirs and we started early on with ours, which has the ultimate potential time will tell."
Team have been going to great lengths to hide thier rear ends with many cars being covered in the pits and at the launches however you can find shots of all the diffusers here.http://www.racecar-engineering.com/articles/articlesgallery/26022/1/0/f1-2010-diffusers.html