I just had my 2nd floor bathroom completely remodeled, down to the studs.  Now that the renovation is over, I've noticed that the portion of my ceiling, just outside the shower is starting to get moist.  I have a panasonic fan installed that is rated for 110cfm (room is about 9'x7').  I want to upgrade to a stronger bath fan, I'm looking at ones that are rated for 190 or 240cfm's.  I know that it is probably overkill but are there any negatives to this?  I paid enough for this remodel and don't want to keep a door open or open a window while showering.  Any thoughts or advice to prevent this moisture are appreciated