Neil, the stack pipe i have i will re use it was all the other pipe work thats being renewed, mines is just a length of pipe fixed to the cab with some bends in it to connect to the silencer box, it has no flex fixings or mushroom bottom to it. i place a can over the top of it if the hogs not working to stop the rain getting in, never had a problem with it rusting away or breaking off its mounts with over flexing.