Don't know if the 17 x 8 wheel will fit your 300TD wagon, but the extra 1/2" width of the wheel would be split evenly ... 1/4" on each side of center. The edge of the wheel will be 1/4" closer to the fender and the strut. Check with a tire dealer as 215/45-17 tires may fit on the 17 x 8 wheels. Then you will need to confirm that the 17 x 8 wheels don't interfere with any suspension components.

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Fred Hoelzle