My EX is 10 yrs. older than your gf's and it occasionally makes a creaking noise when I put the clutch pedal in (disengaging the clutch) and sometimes when letting it out, but less often.
I've only noticed this when parked, probably just because it's not quiet enough (traffic, etc.) while driving. I'll notice it one day and not another.
I've driven multiple cars though that made the same noise, some hondas, some not so I'm not concerned about it.

As far as replacing the spring or what the popping sound is I dunno, sorry.

edit: Just thought of something, assuming it's actually the spring making the noise and not the cable or slave cylinder or something like that, it could be that the spring isn't seated properly. I think I remember reading someone fixed a noise by adjusting the spring so it was seated properly.
Just putting it out there.