IMO in a 10/12 point typical 8.50 cert cage you will likely see a 30-35lb weight savings with moly over mild steel. I think many people go Mild for cost reasons. The material is less money and in some places easier to come buy and also can be mig welded. Which means less fitment time and a lower cost. I know you didn't want that but for a typical 8.50 cage it is not a ton of weight but in racing weight is weight