Have you tried Vinyl Die, it works really well.
Messy shit. You will dye everything you want plus your hands, and everything else you don't want that happends to get in the way. I would only suggest doing this if you could remove your panels and do them one at a time out of the car. In the car, it will be a pain in the ass. But the stuff works great. I used vinyl dye on my old trans am.