FatMat is asphalt, Sound Destroyer is asphalt, Peel & Seal is asphalt. Do not use these in a car.
eDead is butyl but it lacks a decent foil facing. This means you will have to use more layers to get the same result and so you pay more and have to do more workj - poor value. The adhesive is OK on the v1SE², but several people have had problems with the v1² peeling itself off.
RAAMmat is the cheapest butyl product you can buy. If you don't want a full roll, e-mail them and see if they will sell you 1/2. If not, buy as much SS Damplifier as you can afford. Either way, you aren't going to be able to do layers and layers in your trunk. Just spread it out and use most of it toward the centers of panels and away from bends and welds. If the panel rings when you tap on it, add some sound deadener. You are much better off using less of a decent product than 2 or 3 times as much crap.