Decal replacement.

Take your rig to reputable sign company. They do this stuff for a living. They will know the best way to remove it without damaging the sides. I would also talk to them about the new graphics. They will use high-performance vinyl that will outlast by years the intermediate vinyl garbage* that your old ones are made of. Depending on the colors and how you care for them, you could get as much as 10-12 years or even more out of the new ones that way (7 or better if you have reds or variations of red).

*can't believe it some of the words that are censored!