Quck question to add to this thread. My used model M is great but the spacebar is just the slightest bit. . . firm. I generally give the spaceboard a solid thwap, regardless of the board I'm using, but compared to the other keys, it's got a little sticky roughness I'd like to smooth out. Would silicone grease on the same parts as well as the clamps for the metal bar do the trick? Do I run the risk of 'overgreasing' it and ending up with something TOO smooth or soft?