Spark plug OEM BMW or Denso

Either one, but I found the Denso to be cheaper and easier to get. No issues with them.

You can usually find DENSO IRIDIUM Spark Plugs , which are the OEM Supplier, for about $15 each at any Advance Auto or other major auto parts store.

Yesss got denso coils and spark plugs off their site and they have been great

And, before you get too far, are you replacing with the right plugs? I presume it’s the 2AZ 4-cyl since you’re not asking us how to get to the back plugs. The right ones are the Denso Iridium Long Life or the NGK Laser Iridium.

I had similar problems with mine until I tried stock F80 M3 plugs. Mfg #12120039634KT1. Mine was 07 N54 FBO.

I use Denso IK20TT and these spark plugs work every time, on both fuels.

I put denso 5310 in mine, apparently they are supposed to give you a slight increase in power if you use premium fuel.

Idk if I gained any power, but the car runs well.

For what it's worth, I've changed my plugs twice (OEM to Denso to Beru-RS7) and never noticed any oil or any difference in color between the plugs.

I have the 24's, not impressed.

the densos work fine, the point of swapping is not for any performance gain, rather to prevent shattered ceramic from raining into your cylinders