[BmwF87N55]

Hi guys
I own M2 N55 2016 with 92,000 KM
I'm in process of deciding if I'm building the correct engine or replacing it with imported one
Had an issue at first of "misfire cylinder 6"
Which lead to camshaft replacement
Replacing piston rings ( Aftermarket )
Problem was fixed ( or so I thought ) but since then I'm
Experiencing the following issues :
1. Black soot mixed with water coming out the exhaust every cold start
2. Excessive oil consumption .
3. Excessive fuel consumption.

The questions are as follows :

1. What is the best thing I can do now?
2. Has everyone here deal with this type of issue before?
3. If I want to rebuild the engine with more robust parts is there anything I need to change or improve around the engine?
4. Any recommendations about parts brands or where to buy a new engine

Please advise

[BmwF87N55]

Anything? Someone??

[Carrera2RS]

Take your car to a specialist who can diagnose the problem as much as possible before stripping and rectifying. No clue why you replaced the camshaft after a misfire BTW