For the front badge, remove the grille and then pop off the mount that's clipped into the grille. Heat the mount up with a hairdryer - softens the sticky pads. Remove the badge letter by letter. If you want to get the spacing spot on, remove and replace one letter at a time. Before you stick on the new badge, heat up the sticky pad. Press and hold.
Mine have been on for more than 18 months like this.
For the rear, use low tack tape to create markers for the letters. Again, heat up with a hair dryer. Use dental floss to remove the letters.