No racer has ever lost a race because of the undercoating on their body. BOMBSHELL bodies with the lining have been track tested and weighed 4-8 grams lighter than the competition, which did not have the lining. 2014 Stock Nationals Short Course Champion was a Rhino-Lined BOMBSHELL. In a class as competitive as that, and on a large body, what more evidence do you need. Refer to the first response.