you need 1/2" and i torque mine down to 150Nm
erm yes it does
a 1/4 even if it did go to that high, which none do, it would break before you got to 100 or so nm
3/8 same story
yeah and dont they say they are only aqurate within 3/4 of there scale ie stay in the middle of it?my 3/8 snap-on wrench goes to 100Nm.