I'm using half a can in my 4 quart sump (I think a little goes a long way when its added to an oil having some moly in it already, as Syntec does), and its never affected my idle, although in another thread an increase in idle speed was reported by some users of it. Initially I was going to use a full can of it, but I just had half a can on hand when I did my last OC and never got around to getting another one.
LM mos2 is one that's really difficult for me to post any kind of quantified results with, but I add it anyway on the basis of it being cheap recognized for its friction reducing AW properties. Its the only oil additive I'm using this OCI, although there are some other LM products I may try later, in addition to mos2 (on another OC).
-Spyder