if it's just a roll bar or an 8 to 12 point kit in a standard door car they just like it to be mounted as high in the body as practicable to meet the spirit of the rules. But any National event caliber tech inspector wants to see the 3 inches in a full tube chassis car for safety issues due to fiberglass bodies...etc and they also know any savy chassis builder will ALWAYS try to shave a few inches of tubing here or there for weight reduction. When it comes to saving weight on pro stock or fuel cars it's insane the money people will spend to get a few ounces or pounds off in one place so they can add it in others where it is needed for chassis tuning.