Does anyone know is this a sticker that can be taken off or will I damage the sunvisor trying to peel it off?
Yep, can be done without damage. It's not just a use your fingernail and peel thing though.
How I did it:
Remove the visor, it takes a long time and some elbow grease to get the sticker off.
Spray with Goof-off Pro-strength and use a scotch bright pad to rub off as much of the printing as you possibly can (especially the yellow parts)
Soak a rag in goof off and place it entirely over the sticker. Keep it totally soaked until the vinyl gets totally impregnated (it will expand in get wrinkly)
Peel with a credit card or fingernails keeping it soaked the whole time. It comes off in tiny pieces and you need to keep it soaked. This takes a long time.
Let it dry out and the vinyl will re-tighten.
Use Goof-off to remove remaining glue.
There is a little outline that remains, but I imagine that will disappear in time. Be very careful not to allow any of the goof-off to touch the plastic pieces around the vanity mirror...it corrodes it a bit and leaves white spots (I found out by setting one on a slightly damp rag for approximately a millisecond). My vinyl fully re-tightened once it dried out, but I was a bit concerned because it gets really loose when it's soaked...YMMV.