The first side I used a heat gun and mineral sprits. Took a lot of elbow grease but the cost was near nothing. Second side I used
3M Stripe Off Wheel. Much easier and very quick but I needed 2 wheels.
Once the decals were gone I scrubbed the area with a strong soap mix to ensure I got ALL the wax and dirt off. Used cheep lawn plastic bags, I stopped using since they seem to split open after one mower load of grass, to mask off the areas I didn't want to paint. Also I picked up a roll of 1/4" tape to mask the tight bends of the original graphics. The wide tape doesn't bend as smoothly as narrow tape.
I also did a very light sanding with wet 600 grit paper before the final coat which gave a very smooth surface. Spray cans can splatter a bit.