Matty, did you drill a hole on each end of the crack to stop further cracking by notch effect? If not the crack will slowly expand further even with a supporting plate.
Yes you have to use a magnifying glass and drill the end of the crack to give it a rounded stress-point free end. Thats what they do to planes I beleive. I am sure MDH knows more about this!
I have heard of them cracking before. Hence why the g56 kit uses an uprated exhaust mount.
Id the crack coming from an echaust mount hole?
I wonder if rubber grommets/ washers would be ki der to the interface?
Did mmc fix your light cluster?