Where can I buy it in a large quanity for a good price? I hear brown bread works really well? THe application will be in the doors of my 1991 civic hb. Basically im trying to get a "little more" out of my mids and make the door sound a little more solid so I plan to cover the entire inside of both doors. Will I notice a very large difference in midbass output?

If the speaker is just free air in the door I bet you will notice some good things when you add deadening...

Id paint the inside with some liquid shat (especially behind the speaker) and cover the outer with mat sealing the back of the speaker off from the front....

Also heard a lil trick where you attatch some styrofoam (or whatever you got) up in the door at the opening for the window... supposed to help midbass in some cases...

Cascade is the easiest stuff I've used to date.

It's expensive though.....but a door kit should do 2 doors no problem.