If you are taking the material off the bottom of the jug you must make sure that you don't have a ring ridge. If you do in fact have a ring ridge and you don't relieve the cylinder it can mean big ring trouble. It's doubtful since most of us have low mileage but definitely something to watch out for. If you remove the material from the bottom the piston rings are going to travel farther up the cylinder wall than before by the amount you removed from the bottom side.