A number of people in the UK have done it , in the UK the M3W does not have an emissions check as part of the annual MOT.
My understanding is the adaptive ECU control means a retune is not required.
I agree probably not something to do if you are in warranty , and want to keep it. You could also argue the worth of the Morgan warranty outside the UK
Going back a few years I have read on here folk in the US doing it , but cannot recall locations sorry.
I also dont think I have read any positive or negative knockons of doing this, other than its louder - I was just putting the suggestion out as the first post in the thread mentioned removing baffles in the exhaust, and if you are doing that it makes sense to at least consider removing the cats.
