chassis saver is a competitive brand to por 15. imop it is better. the chassis saver gloss black seems to hold up pretty good on what its intended for (chassis, frame, floors ect) not sure how it would last in a direct sunlight application. i have the gloss black under everything on my 66 pontiac, and still looks like the day i painted it. however, the satin black that i used on my rad support, and inner front fenders, turned kinda chaulky after a year. i use this all the time, and would recomend it over por 15 any day. its called chassis saver, from a company called magnet paint. awsome stuff.