And apparently the "design" is God doing some genetic engineering (aka guiding evolution to some degree). Now, the question is, how does one tell the difference between a Godly genetic tweak and a non-Godly random mutation?
No. ID makes no attempt to identify the designer, it only infers there is a designing intelligence behind many of the features seen in nature. The designer could be the Christian God, a Hindu God, (in some contexts) a super-intelligent alien species, or any from a host of other potential intelligent entities (known or not) - but ID doesn't care.
I massively suspect that the vast majority of ID proponents (including yourself) have the Christian God as being the designer.
I would assume that the method of design would involve some genetic engineering. I'm not sure what you mean by "guided evolution", as that term is somewhat an oxymoron, though that may depend on how you define "evolution".
Biological evolution (and I throw out this definition as being a geologist, not a biologist) is the change in a population from genetic change through time. Your "intelligent design" is changing the path ("guiding") evolution would take without the "intelligent design".
As I recall, Michael Behe (one of the big guns of "intelligent design") is a big believer in the bulk of mainstream biological evolutionary theory.
That is a bit of a vague statement, but IMO that would not be an accurate characterization. Behe in the past has indicated agreement in the idea of Common Descent, but he does not subscribe to M+NS as the sole mechanism.
Common decent is a chain of genetic change. Certainly Behe does not subscribe to M+NS as the sole mechanism. More like M + NS + ID (aka divine genetic engineering).
qsDesign" is at best an undetected and probably undetectable detail in standard biological evolutionary theory.
No. Design would be detectable, or at least inferred from the data.[qs]
What we see in life is more the picture of non-design or bad design.
Moose