Wouldn't change : -
Unique M body
M suspension tune
Parts bin availability for future maintenance. ( Good point mentioned by OP )
Lightened flywheel. ( I would prefer even lighter )
Options list. Take it from stripper to all the fruit.
CSL type wheels. A lot of people comment on the wheels to me.
Compact overall size.
Inline 6 cylinders. ( My favourite configuration )
And most important - Fun factor