This may seem a strange question. But Has anyone tried to polish the internals of air flowing areas in there Turbo. I don't mean enlarge it changing the AR but simple polish to a better finish to improve flow.
I am in the process of building a 998 Turbo with a T3. Not ideal. I have been researching every way I can improve spool. This seems a favoured option by many people but not referenced for Mini.
Thanks
Rob