Offset
But that shouldn't matter. If you got 17's in the same offset, which are usually 7.5 or wider, you would be cutting slices in your front strut.
You need to do a search here on this topic and you'll find that in a 17 any more than 7.5 and offsets outside of 35-37 is asking for trouble. Tires should be 215/45-17 to be safe, though some get away with 225.
Take a look at (our sponsor!) TireRack.com. There are recommendations there and you can even look at different rims on your model. Good people!
If their rim choices are not what you are looking for, a good source for nice priced MB rims (nice "replicas") is TheWheelExchange.com.
I just bought a set of 17" Alutec DTM (AMG Monoblock replica) for $589.00 from them including stainless lugs and MB star center caps. Very pleased with dealing with them and the quality and finish of the product. Got the tires from TireRack.



