There's a special place in hell where people are removing clear bras from their Subarus. The one on my car has been baking for more than 7 years. It is cracked and looks like crap but it adheres to the hood remarkably well. The pieces come off about the size of your pinky fingernail.
Here are some of the methods I've used-- none of these methods has worked particularly well.
1. Steam-- I've used a commercial wallpaper steamer-- the result was marginal.
2. Adjustable heat gun and plastic putty knife- worked OK, but left a lot of residue that still needed much work.
3. Adjustable heat gun with single edge razor blade-- good for removing on flat areas, very risky to paint.
4. Goo Gone or Goof Off. Goof Off worked better. Helped remove residue after heat treatment.
5. WD40-- this worked reasonably well as it was applied to the hood and covered with a garbage bag for a few days. Still not what I would call success.
Anyone have other suggestions? Anyone used ammonia like for removing window tint?
All said and done, I would not put this on again, nor would it stay on so long (it came to me like that). I think it would be much easier to simply repaint when the time came.