Sound Deadening

Hey guys, I'm in the process of deadening my trunk and I have a question. I have (2) vents in both rear quarter panels just below the floor line of my trunk. I plan on applying deadener all around those vents, but should I apply it OVER the vents as well? I know these things are designed to relieve cabin pressure or whatever, but what should I do with them? Here is a pic:

Sup, My sunroof is clapping pretty bad with my current setup and I'm planning on doubling it, so I wanted to know if anyone has been relatively successful controlling sunroof clap. I only have problems when giving demos and competing, since I don't bump it (full tilt) on the daily. I use my sunroof, so I have no plans to glue it shut or permantly disable it.

I am going to be tearing up my car for a wall build and I want to sound deaden as well. What material can I use so I have similar effects as MLV (Mass Loaded Vinyl)? Basically I will be looking for a heavy, flexible material, that is on sheets and does not smell awful. I'll be going through our big shops for construction and whatnot, but you guys can suggest other things and places I can look into.

Where do I need to apply sound proofing to these doors?

So I just popped off the door panel for the front right door of my fusion and I realized that there is a metal piece that covers the actual inside door part. Should I take off the metal piece and do the inside door or should I just put it around where you can see in the pic. I'm using the SDS CLD tiles now and possibly later doing the other 2. Just want to do what's best. Thanks!

All, I have posted about every aspect of my install except for this one. I have a 2008 Cobalt LS Coupe and have very recently, 1 Hour ago, bought a new set of speakers for the doors. I have never deadened a door before an am looking for information as to where the best locations for each type of deadener would be and if your regular "sound mat" would be good enough. The picture below shows what my door looks like with the interior panel taken off. Any help would be much appreciated!

I have an 02 gmc extended cab truck. Im currently running two AQHDC3 10s powered by an saz3000d and will be installing a sax100.4 later. Right now im getting lots of roof flex and rattling. Was curious which I should get if only running the amount of said power? Also how many layers and where.