I personally don't notice any filling at all. IMO, any wax/sealant that deepens the paint will hide *very* faint marring. What I mean is, if you had a perfectly polished black car, someone washed it with a dirty brush, then you applied Z5 *only*, it would look better, but it would still marred to heck.
It's not going to fill anything that you see in 1000 watt halogens.
I find that Z5PRO darkens the piant a little more and is a touch slicker after it cures. I prefer it to Z2PRO for some reason, perhaps I just use it more. :nixweiss
Either way, I don't think it really fills--especially at the autopian level.