my WIFE has the bag it-BUG

She wants her grand cherokee bagged after seeing one at Blood Drag this weekend. I talked ot the guy a lil bit about his, but I didn't ask about the cups. Anyone know anything about doing one of these? What size DOM will I need to make bag cups out of? Anyone done one? Leave me a post and give me some kind of hints/tricks when you read this. I am excited about her getting the "BUG"