I was talking about rigid collars, no kidding!Sounds more like you are talking about the PCI bearings, not the Spoon rigid collars?
The rigid collars are designed to eliminate movement of the subframes by filling in the gaps between the mounting
bolts and the subframe holes/slots with aluminum. They function like a crush washer but a more complex shape to fit the application.
They need to be installed correctly in order to work and the directions are not obvious. I had to inquire with Spoon to clarify, and they
responded promptly with an updated pdf of the directions, which was much appreciated.
Also, the rigid collars come with anti-seize, which some may mistake for grease, since the tube has Japanese characters on it.
I didn't use the anti-seize because my car will never see winter or salt.