I started with some knockoff clear shells and used this plus this for mister chef's but I think I used too much black. For barbieter, I used this and it was way more pink once done than I wanted. It probably could have used some black or blue added.
Both color sets were put in my heated ultrasonic cleaner at 50c for 20 minutes then removed, washed in cold water and allowed to dry. Heads up, the dye packets come with an intensifier, I used it on both but it has a weird chemical smell that lingers after you take and wash the parts. About a week on, they don't stink anymore.
The shells themselves were mid quality. The d-pads are super sloppy and the buttons stick so I used the original buttons from the first party shells. The gold shell I bought for the green accents needed the shoulder buttons and select button adjusted, it also came with 2 left triggers... Overall, I like how they came out. I wish the green was lighter but thats my fault. I may do some backlights or something in them to accent it but for now, its a unique setup and not sticky with 20 years of Doritos powder and baja blast.
I would look up the specific material you like to print with and see how it takes to dyes. I don't imagine filament would work super well, but then again you're meant to store them in low humidity containers, so maybe it's hydrophilic enough to absorb the dye?
Resin on the other hand works really well with dye. I don't have much experience with dyeing finished prints, but you can add a few drops of alcohol dye to white or clear resin for some amazing results. Coincidentally I have a master chief helmet that I printed in two parts, helmet and visor; the helmet came out a little too light and pastel looking (used white resin and green dye with a few other colors until it looked right enough), but the visor (clear resin, orange and red dye) is badass.