And to add to BadVision's post, a bit more research will help too. I just posted not a week or two ago about using SEM (not SME) paint on dashboards and how its held up for the past decade in my truck that I still own!
Search here and the other toyota forums, read through the related threads THOROUGHLY, I'm sure you'll find answers and personal experiences with seat dyes and paints. And fyi, SEM paints are also capable of "dyeing" seats and carpets with their spray paints. I've never used it on carpets, just replaced mine with new carpets instead, but I've personally read through, and viewed photos, of painted carpets using SEM paints.