Did some searching and seems like some Cadillac owners have similar noises with their Eibach springs and Eibach sent them this as a solution.
Maybe we can call Eibach to see if they have an application for the F10. This just slips right in without the need to remove the springs.
CTS-V's Eibach part "(UB0205-5) for a spring isolator"
Some people also used this instead -
http://www.radioshack.com/product/in...ntPage=search#
Not sure how well that works without seeing it in person. I might to check it out to see how thick/soft it is to be able to handle the task
Alan