I have leveled-up Bowser to Level 99 in Mario & Luigi: Bowser's Inside Story. While I am relieved that I have reached that goal after several days, I am quite disappointed that when I defeated the last boss (Dark Bowser) and watched the ending credits and epilogue, nothing was changed after Bowser and the Mario Bros. reached Level 40. It seems to me that doing "100%" was a waste of time and effort.

Now if I can try to get an "A Rank" on the Cholestroads and Broque Madam minigames...