With regards to the US FMS (Foreign Military Sales) process, Section 36(b) of the Arms Export Control Act (AECA) requires the President to give Congress advance written notification of the intent to sell defense articles, equipment and services.
- 15 days prior notification for
NATO, Japan, Australia, and New Zealand for
-- Major Defense Equipment (MDE) valued at $25M;
-- Defense articles or services $100M;
-- Design and construction services valued at $300M.
- 30 days prior notification for
all other countries for
-- MDE valued at $14 million or more;
-- Defense articles or services with a total value of $50 million;
-- Design and construction services of $200 million or more
So you can see that advantages in the FMS process are in place for NATO members as well as Japan, Australia, and New Zealand.
For further information on the FMS program, have a look at the
DoD Security Assistance Management Manual.