it doesnt smell at all. inside the car, i dont notice a thing, and even when the door panel was off, i didnt even notice it. (or maybe i was high on the fumes

).
just put it on the bare metal, behind the foam. there is also another well behind the 1st thing of bare metal, where the crash bar is. you can put some there too.
you need to peel the foam off carefully. it goes back on fine, you dont really even need adhesive, the tar stuff will stick back on to it.
one note: when you put it (peel and seal) on, just make sure you dont cover the holes that the door panel spikes go into. i think there are like 2 holes that shouldnt be covered, you'll see when you put it on.
i learned that the hard way ("why the hell wont this damn door panel go back on?!?!"

)