Which Color Remover Won't Damage Curly Hair

Hello,

I'm Caucasian and my hair is naturally curly and black with about 10% gray. I have used dark brown (black dyes are too harsh and look dull) permanent dye and most recently, dark burgundy permanent dye to cover the gray. I'm wanting to dye it a pink/purple or red without bleaching as the bleach really wrecks my hair and destroys the curl. I've seen the pages of dark brown dyed hair without bleaching and some of the results are quite nice - with Special Effects Virgin Rose and other colors in the red/pink/purple family. It's also difficult to tell just what colors work on really dark hair as many of the posts on those pages don't say how dark the hair was before coloring. I'd like to try one of these Special Effects colors, but wonder if I need to remove the permanent color first or if I can just use the Special Effects color right on top of my currently colored hair. I know it's nearly impossible to dye over hair that has been dyed a permanent dark color. Has anyone with naturally curly hair used Colour B4 or another product that didn't ruin their curls? 

Thanks in advance for any help.