The 3M 7517 Decal Remover:
https://www.amazon.com/Scotch-Brite-.../dp/B00EW7MUQ4
Will remove any decal and most of the glue. I’ve used it to remove old, faded, and cracked decals on my old 1997 Sea Breeze and my 02 Montana. It mounts to a power buffer. Took about 3 days to remove decals from the Montana. Buffer gets heavy. Used Good Off to remove remaining glue.
The shadowing was extreme..PO had it in Nevada. The blue tape indicates where the decal should be placed (aligned before I removed old decal). I then started with 220 grit and worked my way up to 1000 grit wet sanding with random orbital sander, removed all of the shadowing.
Then I used the buffer with wool bonnet and polishing compound to bring some shine back. I only sanded and buffed the areas where the new decals were to go.
All of the decals came from broadstreet decals on EBay. The mountains and Montana decals were very similar to the originals. I picked out the “swoops” from their online selection. Applied using the “hinge” method.
The stripes were a different story. I didn’t have the energy to sand and polish so I removed them and placed a 7 inch wide blue tape where the stripes used to be. The tape covered all of the shadow lines. I then applied ˝ inch white and brown tape over the blue tape in order to produce stripes. All stripes applied using the water technique.
All in all, it took over a week to do, and I wouldn’t want to do it again. Total cost was under $600 not counting my labor.