Rims for w208

[pkc168]

I have a 2002 CLK430, did quite a bit of research and was sure the fitment:

18 x 8.5 35mm offset front and
18 x 9.5 38mm offset rear would be the correct staggered configuration

I just purchased the wheels and put the 18 x 9.5 ET38 wheel on the rear.

Looks like it would not fit, since the rim rubs the plastic inner wall. Is this right? If I put the tires on, will it fit correctly, or will it rub against the inner wall? Is there modification to be made? can somebody shed some comment on this.

Thanks,