it depends if the old girl is a rough and ready monster then definatly skirts off, if she is a elegant lady with no wrinkles(dents) then definatly on but i cant stand bent sills i would rather unbolt them and do what i am doing now which is to make up a set of box section sills which is bashable then put the good ones on later when you are not going up in the forest chasing LKTs, MTZs, star 660s, and praga v3s