I have the whole berk rebuild kit with an A2 aluminum impeller. should i go through and sand the inside of the pump to make it smoother, or do you want it a little rough? this is not a race boat nor am i looking to make it one in the near future. just trying to rebuild it with fresh stuff inside, the previous owner had this boat for 13 years and said he never touched the pump. would it help to extrude hone the bowl or is that throwing $ away that could be used somewhere else?