Though the rules are PG-13 regarding sexual content, I've seen a fair amount of gore go unpunished by the staff in roleplays (although they potentially just didn't see.) My advice is simply not to be tasteless about it. The only way you'd go past the line is by being tasteless - as in, anything extreme enough to cross that line would be lacking in taste. Use your common sense.
My personal view is along the same line. If you're using torture as a genuine device for exploration of a character's psyche under extreme duress, or for any other reason that could be considered legitimate in literary circles, go ahead. If you're using it as a shock tactic, or for the sake of being #OMGSOEDGY, please, don't.