06-28-08: CytocycleYou're right--the tonearm wire in the SL1210 M5G is pretty good and I haven't had any urge to change it. The tonearm leads in their headshell is another story, however. I just got a set of the silk-wrapped litz ofc cart leads; I'll install 'em in my Technics headshell and see if I notice a difference.
The Technics M5G has pretty good OFC copper wire leads.... so this update doesn't make as big of a difference as all the other Technics tables which don't have the upgraded wiring.
Do you have a link to the lighter AT headshells? The lightest I've seen is their magnesium one at www.audiocubes2.com, and it weighs 11g, which is 3.5g more than the std. Technics.