If you can't get it off of the leather, you can re-finish it. The "dye" on the leather is actually more like a paint. You can strip the old off and re-finish the whole thing if it comes down to that.
http://www.Leatherique.com has a re-finishing kit that's fantastic and they even carry Porsche colors or they can color match yours.
I hope it doesn't come down to that, but you don't worry about having to replace it all.