M3 UK 103k miles. Not supercharged. Engine went for rocket gasket and found r/h vanoss exhaust spring not in the correct position (unknown reason). Both vanos covers where missing. On the l/h found both cracked.
Found them on the sump and plastic particles found on rod bearings too. Engine requires rebuild.
It didn't blow up but it was close to.
https://www.m3post.com/forums/showthread.php?t=2114569