Here's a thing. In psychological tests, individuals feel that kunt (with a k) looks more offensive as a word than 'cunt'. It is to do with the the fact that 'k' is considered 'harder' than 'c'. I don't mind really, I lick 'em however they're spelt.
Depends on the context and the woman you are with. Socially I hate swearing, but said at the right moment saying the C word gives nothing but pleasure mmmmm