If you were to work on your car, replacing a oil pan, tranny,diffs, heads etc and pulled the gasket off would you not replace it??? Even if it didnt seem to have anything wrong. I would. I realize this aint a car but same principal would apply. Also going from grease to silicon you want to make sure to clean all the grease out, including the grease off this gasket. Besides mugen seiki comes with the same size gasket with about 10-12 gaskets for about 4 bucks. Holes match up too.