I recently purchased a 1997 M3 sedan and I am having a ball! One problem I face is that I need to drive it into the Sierra Nevada mountains about 10 times each winter for snow skiing. (I know I should have bought a 330xi but..) The owner's manual and common sense say you cannot put chains on due to the limited clearance between the tires and wheel wells. I am considering a clamp on type of wheel traction device known as "spyders" or a separate set of wheels and tires, which would allow chains. Do you have any suggestions?