My 2009 factory offsets are 28mm, front and 33mm, rear. The Sport pkg models are 25 and 28. Same wheel dia and width.
I have not found a reference that gives alternate offsets, however, The Tire Rack site does give alternate diameter wheels for specific models. The offsets for those wheels are listed. http://www.tirerack.com/content/tire.../homepage.html
The 20" staggered wheels listed there, for my car, have 30mm front and 35mm rear offsets. For a 2013, the 20" wheel offsets are 35 and 44.
The body changed in 2011 to the C218 chassis. I expect it would be likely that you will get some rubbing if you put a 35mm offset wheel on a car that was designed for 44mm. Especially if you lower the car.