I just replaced my plugs and coils on my 2018 M550i. I had a bit of a lumpy idle with no codes and no air leaks, etc. Gas was good so it wasn't that as it lasted through multiple tanks of gas. After the change the car runs smooth as silk. No idle issue.
I used NGK Laser Iridium SILZKBR8D8S, stock number 97506 and the Dinan coils D650-0002 which are just about as cheap as stock or aftermarket ones. The Dinan coils require a minor mod that is easily done w/an exacto knife, etc.
You need a thin walled 12 point 14mm spark plug wrench. My Facom thin walled one was not thin enough so I had to use a buddy's CTA 2376 socket. Pro tip, spray the inside with silicone spray if the socket pulls off the extension. It'll help the spark plug slip off easier, but it will still hold it as you extract/insert the plug.
Torque is 23Nm. I used this youtube video for a 750i as a how to:
N63 spark plug replacement video