Most people just replace the entire center cap with knockoffs from Asia. Aliexpress did have some nice ones, but they're hard to find due to the fact that sellers can't use the term "Porsche" in their ads.
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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.