Just as an example:
If I have 130 reputation and provide 50 as a bounty for a question, do I lose any of my existing privileges (due to the 130-50 reputation)?
Yes, due to the bounty rep being 'spent' - as your new rep would be at 80 (i.e. not able to downvote until you reach 125 again). But, with good contributions, you'll probably be able to reclaim it in a short amount of time.