I just bought a 1998 z3 2.8 and brought it to a locate dealer for inspection. They recommended new shocks, radiator, tires. I went and had them install a new radiator and I had another company install new tires. I am going to install the shocks myself. The car has a shimmy at about 45 MPR, tires are new and just balance. Could this be a bad shock issue? or perhaps a tire threw a weight? other reasons? thanks