Yeah leave the decals off the car unless your sponsored.
Rub the old decals off with alcohol. Let air dry, then wash down with cold water and a clean cloth and let air dry. Then apply the new decals smoothely and rub them down once they are on with dry cloth.
Call your local Evinrude dealer and give him the model number and the year. Some of the older ones are still available. If you have any problems send me a email I might be able to track some down.