Great information, 80stech and BimmerBreaker.

Isn't part of the purpose of the extraction tool to help remove a stuck injector without damaging it?

I found this kit on eBay:

https://www.ebay.com/itm/386461217581

Hard to tell, but the upper and lower o-rings look the same. No mention of the silicon compound o-ring. It only gets below freezing a few days a year here, so that may not be needed. I searched Amazon and didn't find such a kit for N62.

@BimmerBreaker: Did you take the engine out to do your rebuild? If not, is it straightforward to get the rails out and the injectors out with the engine inplace?

How do you get any stuck on o-ring material out safely?