Meaning : To the degree or extent that.
Example :
Insofar as it can be ascertained, the horse lung is comparable to that of man.
So far as it is reasonably practical he should practice restraint.
Synonyms : in so far, insofar, to that degree, to that extent
Meaning : Used after a superlative.
Example :
This is the best so far.
The largest drug bust yet.
Synonyms : yet