[Coleydog]

Im ready to do a ballest box in the car and need some insight on how and where one puts it, photos would help. I know the rule book explains this but kinda vague to me and whatever you guys have made does work. What's used for weight? Lead? I guess it would have to be removable or added to go up and down a class, right? Any help would be appreciated.
Oh yea forgot to add, I want to incorporate this into the rear cage bars if possible.