That sucks, it happen recently to member that had a Dinan stage 2 tune on his M4.
The dealer immediately passed the buck on to Dinan, on principal but they ultimately they had to replace the entire motor..
This sounds like your scenario, so a new motor is more than likely. And I wouldn't want a car that exhibits those tell-tale symptoms.
I believe you told me it's a lease and you have no mods, so you can breathe easy that they'll cover it but I would use this life-lemons situation to get me a M2 CS..
But that's just me
Engine warranty void by BMW, DINAN covers.
https://f80.bimmerpost.com/forums/sh....php?t=1614332