i did it my self the first year i had my 89 maxima which had no rust at the time. only place that rusted out on that car after 4 years was the bottom of some of the panels from not spraying the stuff inside the doors. but i made mine at harkness when i did it. tar and like 20w50 oil. lol shot that shit on and never did it again! i wish i was still there to do it to my malibu