I do not know the brand of the material that the school uses for vehicle wraps, but according to them, the wrap should last anywhere from five to ten years, depending if the car is garaged or left outside. About the same as the woodgrain material that is used on the cars to start with.
Just a thought here along the lines of your heat gun. I've used a hand held steamer for removing wall paper in the house before which works well on some kinds of adhesive. If you have access to one it might be worth a try since the steam would not damage the paint. Lowe's carries a wallpaper remover made by Piranha that works well when mixed in hot water. I've used it on walls in the house and it has removed wall paper borders without damaging the wall paint. The wall paper normally has to be scored first, so I'm not sure if you could use a scoring tool without going through to the paint. Good luck. I've seen pictures of your car and it is very nice. IMHO it is worth spending what is required to make it right. Most fans of these cars go for the factory look, so it may be worthwhile especially if you're planning to sell. In the infamous words of Pat Morita..."wax on, wax off....wax on, wax off"
Won't be doing much until after school starts again in January. Once I get a date locked in with both the school's graphic arts and paint & body shops, I'll get the wood grain stripped and then let the school have it. I'll have the aluminum trim powder-coated commercially while the car is in the shop. Hoping for the second or third week in February for the finished product!
My wife and I used the best quality woodgrain vinyl on our Focus wagon in 2002. Wash it and it still looks like new after 235,000 miles and now into the 12th Wisconsin winter. I do use Mequires Next Generation once each year. Just a little wear under the fuel door and driver door handle depression.