Do I have to disable IP logging in CB (and loose some anti-spam function)
Yes, there is no functionality at this time to anonymize ip address logging.
This is planned in a future release where ip addresses can optionally be stored with the last digit set zeroed (same as Google analytics). Everything in CB uses same API for grabbing ip address though so it might be a rather simple addition to CB itself and have added a feature ticket.
forge.joomlapolis.com/issues/8173