[E93Blackhawk]

I read up also that it could potentially be the exhaust valve, because i get no rattle when driving as mentioned, only on cold start up, and I've heard it once switching the engine off.

Is the exhaust valve considered as the golf tee mod - and are these the same thing? Because i guess I can check if so by unplugging valve lead in the boot as so many do and see if the noise is still there i guess.

Im currently not in warranty also, but I'm going to take warranty out that will cover everything and I guess if I diagnose the issue, it can be fixed.