So finally and just on time, actually on the Christmas finish line, I made myself a much wanted present by getting rid of the tiny almost unnoticeable spoiler lip in favor of a REAL rear spoiler!
The candidates were (in no particular order):
1) M8 carbon spoiler from F92
2) ACS Schnitzer
3) 3D Design
For comparison here they are:
https://cas01.autoscout24.ch/custom/146/8085146/15.jpg
https://www.jms-fahrzeugteile.com/me...or-spoiler.jpg
https://cdn.bimmertoday.de/wp-conten...-Tuning-04.jpg
Now I know each one may have different taste/s, preferences, and in my case the ACS spoiler won the contest! Next to an excellent price I got, the ACS is the one I like the most because it is a little "longer" than the M8 one in that it embraces the sides/shoulders of the trunk lid somewhat but not with quite the same length as the original invisible tiny lip did.....
The 3d design, while being for me almost same price as ACS is in my opinion, by looking at it more carefully, too bulky and a little wider than my ideal spoiler should be.
So technically and aesthetically the ACS rear carbon spoiler ticked all the boxes for me!
Last but not least! There were ZERO issues with removing the original spoiler lip on my M850i. 
The latter could safely be removed and NO damage occurred to the paint in not a single spot! All cool thus, as this was one of my fears after reading some contributions here in the forum a while ago.
Now onto the pictures, of both before mounting it and held on top of the tiny lip to see how far the real spoiler goes as compared to the original variant, along with a few taken tonight as I picked up the car this afternoon with the ACS finally mounted. The pics with the new spoiler are dark but I will shoot some pics with sunlight at the next occasion.