Today I took off my door panel for the dynamat. The only way to mat it was to take off the blue plastic. Is that dangerous or a problem. I only did it with one door pannal so far.

 

See this thread:

https://www.scionlife.com/forums/viewtopic.php?t=65529

Take it off, but be careful not to rip it, and definitely replace it when done.

 

It's just plastic sheeting to keep moisture from damaging the interior. You can buy heavy duty sheet plastic to replace it.

It is most effective on the outer skin because it works to keep the sound out of the door where it can bounce and cause other parts to vibrate causing more noise. If you do the inner part of the door it should help keep a little more noise out.

 

If you deaden the door to the point where it's almost sealed (with the exception of the single holes to keep the watter from building up). I did three layers on the inside with 4mils of liquid. I did two layers on the exterior with 4mils of liquid as well as double layered on the barrier deadening between the door and door skin. The speaker has an MDF ring and I've used non-hardening high density modeling clay as well as a sound dampener in the form of an egg-crate foam behind the speaker itself to dissapate standing waves. It's overkill, but it definately brings out the bass in the door.