As jnolte mentioned, 19x8.5 front and 19x9.5 rear is recommended.
If you must go wider, then a major work is needed with body fenders.
There is a member in other forum who's in progress of putting 19x12 on the rear for CL203.

 

O, now that is cool man! make sure you post up pics with your progress, your best option will prolley b to get flares from anoter type of car custom fitted,
although i do remember a shop selling flares for the w202, it required alot of body work to fit them tho,
go over to www.club202.com and do some searching over there, from memory it was a member there, but dont quote me on it.
If you cant find him or the posts/bodyshop, post back here and ill go looking