How can I change a Member # ? I made a member #2, delete that one, made another member, and now I have a Member #3. I want to delete him, and make the next person who registers Member #2 again.
How do I do that?
And for the Statistics Hack:
How do I change the "Total Members"? I want to set it back to 1 again.

You can do it through the Member files I think. /cgi-bin/Members directory.

I've tried that, but if user #3 posted a reply somewhere, and I changed him to user #2 (via the member files) his posts still say "Member #3".
A new user who registers also becomes Member #4 I think, instead of (supposed to be) #3.

Thats normal, it doesn't update the profiles once someone has been deleted.