It means your engine was built in 2000, and likely has a double row IMSB.
Per the Pelican article on IMSB replacement:
Up to engine # M 671 11237 Boxster S 3.2L M96.21 Double Row Bearing
__________________
2000 Boxster S, 6 speed, Sport Package, Litronics, LED tail lights, LNE IMS-B, OBC, Skybreaker wind deflector, Arctic Silver/Graphite Grey
|