Is your car built after 07/2013?
If yes, you can buy HJS catted dp with a dedicated ECE homologated cat that keeps car EU6 and is guaranteed by HJS not to generate dme error codes/CEL (without any lambda spacer).
I've it on my M235i and I'm very happy with it.
See my review
here.
Fabspeed has also a catted dp that has a lambda spacer integrated and should not generate CEL...