I remember seeing some posts recently about a similar noise in other xi's - sounds like you are riding directly on your springs when it is below freezing outside. I tried searching but could not find the posts. I seem to think it was a bushing, but I can't remember if it was a control arm or a sway bar bushing. Anyone else remember or can find the posts?
Mark

Nevermind, I searched again and it is the stabilizer bar bushings.