i have a 190e2.6. The manual says the stock offset is 49mm, for a 15x6" wheel. I bought a set of 15x7" Borbet ReplicaII (like the 8-hole in the 190e Sportline or 400e), and the dealer asked me very specifically what model benz i had. Those Borbets had an offset of 36mm, which made them stick out approx 1 inch outwards per side (making the track 2" wider, front and back). The wheels look very good on the car, almost flush with the bodywork, but definitely engineered for proper suspension, steering and bodywork clearance (i must admit i was skeptical that it might not fit at first). And they look very stock benz.

As an aside, the Borbet ReplicaII looks very attractive, since it has a flat shiny surface extending to the lip of the wheel, giving the illusion that it is more than 15" (this, compared with the 8-hole of the C-class, which is of a deep-dish design). This makes it also easier to clean.

My only misgiving about this wheel is that it uses special-size bolts with cone-shaped seats. The stock wheels have ball-type seats. Since my spare tire uses the stock wheel, i have to remember to have the ball-type bolts of the spare with me everytime.

Also, the Borbet bolts are of a different size from stock or anything on the market, and i have yet to find a wheel lock for this Borbet model (maybe someone can help me here). Not even McGard has one this size.
Not even TireRack was able to help me on this, either.