From: Vancouver, B.C. Canada
in the case of the 32123S -> 40125S I would say you are truly over clocking the drive, as in, you are pushing it beyond what it should be capable of. This is not the same as when you convert a 40125S to a 48125W, or a 48246S to a 52246S, since they all share the same hardware, the firmware is simply restricting the drive's abilties.
personally, I wouldn't recommend it.
Canada; Leading the world in being just north of the U.S.A.