I have had the opportunity to take my '91 300E 3.0 up to the 130mph range a couple of times on a safe track area but get some vibration that I can't tell if it is wheel balance or suspension components. At 75-85 it's very smooth. I have about 40K on new tires now so wondering if I should rotate and balance. What other components do I need to check and how? I have new struts and shocks all around. Seems like it could be rock solid!!!

Thanks,

sptt