StoutFiles - 7:12 pm on Jul 7, 2010 (gmt 0)
I would change it to "blah blah blah REALLY SUCKS" and then add some facts about how they contacted you to change the title... =)
Editing the title may lower the search ranking. Even though you should be legally safe, mentioning the C&D in a new article would guarantee you would get sued if they're threatening it now, and that would be annoying, so I suggest just emailing them back saying you won't touch the article because it is an opinion piece. If they offer (you can't suggest this) money to take it down, then great, otherwise, just go about business as usual.