i have always heard and read that the fewer accessories you are pushing, the more power you make. i also have a humming noise at low load that i suspect is the idler pulley. i was thinking that i could bypass it (and the a/c) for a few months and that would tell me if it is the pulley and buy me some time to replace it.
how much does a belt cost?
if the a/c doesn't add any drag when it isn't in use, why do people delete it, for the weight savings?
btw, winters in dc are usually pretty mild and it is pretty dry.