"This does not sound like a method for fairly resolving warranty issues, it sounds like a method for consistently denying warranty issues without
giving the customer a fair shot at proving their case."
This seems to slightly contradict your earlier point that by law
they should have to prove aftermarket parts were responsible for failure, rather than
you having to prove that they were not.
Spell Checking:
"He suggested that I take up my issue directly with Subaru of America, and provided
my with the proper phone number."
"This strikes me
a fairly ridiculous, considering that my problem occurred at the factory when the wrong grease was put in the inner CV joints."
Other than that, looks good. Fire it off and let those asshats have it.