High Speed Rattle?
First, I would check to make sure the tires are all properly inflated, sometimes when there is a difference in pressure it can make the car wag a bit. Second, I would look under the car to make sure everything is hanging in there and nothing flapping around (although I think you would feel this at highway speeds not just over 100). Third, the road could be slightly tilted for draining or there may be a cross breeze that can make the car seem to be a bit unstable. Fourth, this may sound odd but I had it happen on a 190D. I left the car parked either with low tire pressure or against a concrete curb. It caused the steel in the tires to bend or become deformed. The whole car shook abit until I had the tires replaced. Fifth, have you had it aligned lately? I had suspension work done on the 190 and it was very jittery until I had it aligned. If you were really pushing the car around corners somethings could be just a little out of alignment. Finally, if nothing else works, it could be suspension/steering problem.
At high speeds small issues can be big issues. I hope this helps, and let me know if you find the cause!



