I have a weird situation. Two of the lug bolts (OEM) on my left front wheel have deterioration of the ball-seat washer.
Apparently this is some kind of soft/low density casting, with a hardened exterior. Two on my track car (hot, hot) have the hardened layer beginning to rip away, with the underlying material disintegrating. Wow.
to shows signs of degradation. Under the conditions of tracking lug bolts become wear items and require monitoring and when necessary periodic replacement.
At some point when track usage reaches a certain level lug bolts should I think be be replaced, starting the season with new lug bolts. It could be that if track usage is really frequent and grippy (race?) tires are being used that replacement after so many sessions or track hours would be called for.
Here's a cut/paste from the manual of my 996 but this applies to the Boxster as well.
4. Always apply a thin coat of Optimoly TA (aluminium paste) on the thread of the wheel bolts, on the shank and between the bolt head bearing surface and spherical cap ring (under the head) −arrows− . Do not grease the spherical cap bearing surface −X− of the wheel bolts that faces the wheel.