Early in my 535's life I switched the transmission (mechanical = "manual"?) to RedLine MTL. It worked great in all environments, including the dead of winter, when the synchronizers worked like it was summer.
One common problem involving rubbing sounds from the front wheel area was rubbing of the sheet metal shield behind the calipers, and it happened while turning usually. It just needs to be pulled back a little. Of course, the problem you're experiencing could easily be something else.