Always just get their name and badge number off their uniform first. Be polite but firm. Know the law. If I remember correctly, it is illegal in GA to alter a car's suspension by more than 3 inches (it may be only 2 inches). I think HB192 was defeated back in 01 that would apply it to trucks though. On all vehicles though, the height of the headlights must be at least 24 inches from the ground, and taillights must be at least 20 inches off the ground.
My Impala has hydros, but I never have a problem, simply because I show that I am not a pushover while being polite but firm. That's all you need to do if you are being harassed. There is no point in arguing with someone who has very little intelligence.