axles i'm not sure but it's not the way it is stock so it may wear them out faster...but not by much

as for lowering your camber will be off and will wear out tires faster

lowering your car will most obviously make your car much rougher to ride in b/c of the reduced suspension travel...when lowering make sure you don't use cut stock springs as they will not dampen the bumps enough to prevent constant hitting of the bump stops

be smart and get a coilover kit that allows you to adjust ride height (like ground control kit)...this is a neat option so you are not stuck with too low of a ride