You are right to say that "specified complexity" is vague - in fact it has two quite distinct meanings.
In the first sense it is true that we find it in life - but that is not surprising. Indeed, life is necessarily both complex and specified and scientists were talking in those terms before the current ID movement started. Evolution is a pretty good explanation for this sort of specified complexity so it isn't much of a point for ID in that case either.
In the second sense coined by Dembski, it would help ID. It's just that nobody has actually FOUND it in life. Dembski's most famous attempt was a complete botch (he didn't do ANY of the calculations he needed to do, and the calculation he did do was irrelevant).
For some reason ID supporters almist never boother to explain which definition they are using.