Mushrooming strut towers revisited: M3 strut mounts vs. "regular" E46 strut mounts
Could it be that the M3's strut towers are less prone to mushrooming not only because many of them come with a strut brace from the factory, but also because an M3 strut mount looks like this...
Versus a regular E46 one that looks like this?
The one on the M3 looks quite a bit beefier. This is a recent discovery for me. da. fuq.