one wire color difference? safe to say that green would go to gray.

 

I know the crimp isn't as good to connect them, that's why it doesn't make any sense to me. I've actually heard it on the BMW boards, but thought I'd ask here and see if it's all O2 sensors or just BMW specific.

 

Splicing twisting and taping works way better than crimps in my experience. Soldering is ideal, but if not, I would just twist and tape them generously and tightly.

 

You can crimp and tape the job to protect it. Splice 4 inches of excess on each side, tie a knot, wound it and wrap it in tape (military field splice) or create a crimped lead wire w/2 female ends on each side and bridge it between 2 splice clips that are on both sides that need to meet. There is lots of ways to do it, some may say some ways are better than others, but if done correctly they all should hold up just fine.