Paul, has your S600 been realigned since the front end wreck? Definitely have the tires balanced with a machine that loads the tires simulating road conditions. It's odd that the 2 different balancing machines disagree ... try a 3rd machine to settle the disagreement. I presume that balance weights are being attached to the inside or outside edge of the wheel, as required, rather than stick-on weights in the center of the wheel.

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Fred Hoelzle