Re: decal / sticker removal ... saving the paint...
I would try the goo gone again. Ive used it many times with great success(old bumper stickers on a buddies car for one). Let it sit for a while then come back and put on a little more. It will soften the plastic and eventually seap through and that sticker should just come right off. Or like the others said use a heat gun but be carfull. Too much heat will take off the paint aswell.