Another option is to rotate the woofer 180 degrees in the cabinet. Sometimes gravity will cause the cone to sag slightly, which in turn causes the voice coil to rub. Rotating the woofer so the gravity is now pulling on the cone in the opposite direction will sometimes (but not always) fix the problem.
Since it costs nothing other than a few minutes of your time, it is usually worth a try.
Since it costs nothing other than a few minutes of your time, it is usually worth a try.