UPS delivers and 1 layer of this stuff and the car is much better. I only applied where you see in the pic - none around the sides or anything. I've had my trunk apart numerous times but it's really simple to get to the areas I did. Nav rattle is gone, it's still loud but much better cruising on the highway. Apparently this is one of the higher end dynamat products...so as far as the material you use goes it may be a case of "you get what you pay for"
Also, I was careful not to cover up this wire. Just slit the material (utility knife to cut it) and the wire is routed over the matting.
