Can have some peace of mind then. I remember how happy i was when i checked mine and found them all to be index 12.
have had my car for over 8 years now and no issues with them...
TBH this index 12 thing is so wellknown and been so for years, so that i believe most n54 z4-s are already on the latest injectors and stumbling on a car that has older problematic index injectors is becoming rare now... these index 12 injectors came out more than a decade ago... in 2013... theres been more than enough time for cars to be upgraded to use them...
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2009 35i DCT Havana brown with ivory white interior. Mods: Cobb stage 1+FMIC, Wagner EVO1 FMIC, BMS DCI, Forge DV-s, Masata Chargepipe, KW V3 suspension, M3 front control arms, Hardrace RTABS + balljoints, Michelin Pilot Sport 4S tires.