That spring has a lot of tention on it and will turn into a U upside down when you loosen the bolts. yes it does have rubber there but the shims also have line up holes so don't mix them up when removed.
Not that big of a jobe but I can't remember how I did mine?
but you need a belt or something to hold the spring when you pull it back into place or you can put the weight on the car down on it to screw the nuts back on the bolts.