SEM is a great product but it is a paint and NOT a dye. It's a flexible coating like it says right on the can. I've used it, and it works well but it is a paint and it can wear and scratch like any other paint. IMO using that on the inside of your new mustang would be the biggest mistake you could ever make on that car. If you want a black interior, you would be MUCH MUCH MUCH better off buying the black colored interior parts. There are no dyes that "soak" into the plastic or vinyl like you(and everyone else it seems) are thinking.