I did a search and ran across this place. No mention of Porsche but they should know Minilites pretty well. Could be an info resource?
http://www.speedshack.co.uk/Wheelnuts.htmEDIT: Actually they do mention Porsche at the bottom.
WHEELNUTS, WHEEL NUTS, WHEELBOLTS, LONGER WHEELSTUDS, LOCKNUTS / LOCKBOLTS AND WHEELSPACERS SUPPLIED FOR :
ALFA ROMEO / AUDI / BMW / CATERHAM / CHEVROLET - GM / CHRYSLER / CITROEN / MOST TYPES OF CLASSIC CARS / DAEWOO / DAIHATSU / DODGE / DUTTON / FIAT / FORD / HOLDEN / HYUNDAI / ISUZU / JAGUAR / KIA / LADA / LANCIA / LAND ROVER / LEXUS / LOCOST / LOTUS / MAZDA / MERCEDES / MG / MITSUBISHI / MORGAN / NISSAN / OPEL / PEUGEOT /
PORSCHE / PROTON / RENAULT / ROVER / RANGE ROVER / SAAB / SEAT / SKODA / SUBARU / SUZUKI / TOYOTA / TVR / VAUXHALL / VOLKSWAGEN VW BEETLE TRANSPORTER BUS T2 T2.5 T3 T4 T5/ VOLVO