This part should always be replaced when installing a new clutch disk. Even if the old one "looks good", wear patterns have been established and the replacement disk will wear out prematurely if it's re-used.
Replaces BMW part number 21 21 1 231 666
This part may appear to be different than the one removed. If the original part has spacers between it and the pressure plate, those spacers are not re-used. This part has been machined to incorporate the spacers and they can therefore be discarded. Always use new bolts when installing this part.