I'll state the obvious again as usual. Since no two chips are created equal in the eyes of geek, overclocking is more art than science. A bit like alchemy, but without the toxic fumes (unless you really go hog wild.)
That being said, I was under the impression the FTW cards were among the highest of the factory overclocks, so maybe it may be in your best interest to leave well enough alone in the long run. It's always a compromise with noise usually being the worst case offender.
On the other hand there are those who enjoy tinkering with their systems as much as gaming, but they tend to have a knack for pushing things further than they should. The moral of the story is, just because someone on the net claims they can push 1.21 gigawatts, doesn't mean it's such a good idea.