I didnt use it in a Z but i sprayed it inside the doors, underneath the dash and on the back of all the dash pieces. I basically put it on any surface that wouldnt let the Dynamat Super stick to it. It helped tremendously, especially with road noise from my tires (i had a 4x4). I also sprayed it directly into the wheel well. Took the wheels off, cleaned it up really good and sprayed away. I think i used 2 cases of the stuff total.
I'M A HOOKER . My other ride is a CH-47D "Chinook" helicopter.