When selecting a replacement tweeter...

[gripracer]

Section 1:
Should one be looking for a sensitivity level EXACTLY at the speaker's overall sensitivity including the crossover? Or a few DBs higher?

This is assuming that I only know the overall sensitivity, and can't find the specs for the tweeter alone.

Section 2:
The stock tweeter is an inexpensive-looking polyamide dome, but it actually sounds pretty good. To get even finer details, I should choose a metal-dome and not a soft-dome, correct?

This is assuming that the midwoofer is a 4" and made from treated paper. It has good inner detail.