Should work with Bluedio Turbine and Bluedio Hurricane H+
By "is this even legal?"
Insert a plastic pry tool between the leather ear cover and the plastic part. There are 4 plastic clamps, placed like a "+"
After that, there are 4 screws and 2 more plastic clamps, for each earpiece.
If necessary, scale 25% on all axis.
Use sandpaper on the yellow highlighted area (on a flat surface).
Be careful with the wire canal/tube, reinforce with superglue.