"You had better not touch that red button, Agent 007, unless you want the entire building to explode. I know you love fireworks, but I would rather we kept this headquarters intact for tomorrow's meeting."

The negative form of "had better" is "had better not" (used for strong warnings).

"Would rather" is followed by a past tense verb ("kept") when expressing a preference about what the speaker wants someone else (or "we" collectively) to do.