They write that the cable weighs 15g so that would make it 118g which is too heavy imo. You mentioned spawn and that is only 85g without cable
Logitech japan confirmed that the MX518 is 146G (with cable) and Logitech US confirmed the mouse was 106g (w/o cable) at launch. If the MX518 weights 146g and the G400 weighs 133g, that estimate of a 25% lighter cable would actually make perfect sense.
40g~ cable - 25%= 10g shaved weight. 146g Mouse -10g =136g compared to the listed 133g of the G400.
My Conclusion/Assumption: Both the Mx518 and G400 weight the same or close too it. (Around 106g)
Edited by Skylit - 6/10/11 at 3:47pm