Hey, I just bought a '98 E39 540I with the 6 speed and Dinan's S2 package (basically my dream), However whenever I take it up to highway cruising speed, 60-70 MPH, I get this odd vibration through the car. when I say odd I mean its not constant, it usually feels like the front end, but I also feel it through the entire body, and it tends to dissipate then come back while I'm driving almost like its being caused by harmonics. It also completely disappears when I accelerate to above 80 MPH. I'm thinking it might be the thrust arms, i had the same issue with my old e34 540, which if your familiar with the cars has a very similar front suspension layout, but there is no vibration under hard braking even from high speed. I have already had the tires balanced and visually checked all the bushings, but I am not sure if the place I took it to used a road force machine. Any incite you may have would be amazing! thanks for all your help!.