Having phoned Porsche today about a few bits for my car the parts person advised that when I renew the coffin arms and fit new eccentric bolts I should be renewing the eccentric washers and nuts also, I had intended using the old ones with the new eccentric bolts.
Old one's are off the car no issue's although I did have to cut the eccentric bolts out.
Doe's this sound correct regarding the nut's and washers ?
I replaced all the bolts, washers and nuts when I did mine. They're cheap enough.
Word of warning though, the washers / captive disk things can cut into the aluminium side of the frame, making accurate alignment impossible without a bit of welding..