yes static, the bodyshop's i worked in both used a piece of heavy chain over the exhaust and touching the floor but i guess a piece of wire and some lug nuts would do the same thing. think of it like your powder coating the entire car, the paint molecules will gain a positive charge when they leave the tip of the gun, if you ground the car then they will be attracted to it. it doesn't work quite the same way as powder coating obviously but the effect is similar plus if you get a bunch of overspray hanging in the air or a solvent cloud as it is sometimes called you reduce the chances of becoming a human BBQ.
