Removing the snorkel affects the jetting, so jet accordingly. It can also decrese the low end a bit, as theres not much velocity through the carb when you whack the throttle open at low speed.
IMO the airbox seems pretty restrictive, so removing the snorkel adds tons of air.
You can be both rich and lean, as in lean in the midrange, and rich on the mainjet, or the other way around.