Can the rear springs top rubber seats wear?
 

hello! i have 2007 v36 G35x sedan, but my rear suspension seems to be the same as Z's.

the problem I have, that I'm gonna change my stock springs to the new ones as my rear sits 1" lower than it should (probably rear springs are too softened now).
I have horrible roads here, so the stock height is what I need!

how do you think, should I change the top conical rubber seats of the rear springs? they are rather expensive (25$ each) and I'm not sure if they can wear at all:
http://i53.tinypic.com/2e4kqvk.jpg

anyway I bought the bottom rubber seats as they are cheap (10$ each).

The top spring perch/isolator should be fine unless it looks visible damaged, cracked etc.