How many parts do you need to replace with US parts on a Norinco M1A to legally add a GI flash suppressor?

Thanks for the help.

I've researched this and I've posted the long version of the answer elsewhere on the Internet and in my book.

Very short version of the answer and the cheapest method: Use USGI magazines only and forever.  Never use a foreign made magazine, ever.  Install a USGI hand guard.  Remove the Chinese flash suppressor.  NOW, install a USGI flash suppressor.  You now have only ten named foreign manufacture parts on the rifle.