Ok, so I just bought my first car and it is already fitted with some pretty tough audio speakers and 2 12 in subs. The subs cause alot of boot and front door rattle.
I've deicded to buy fatmat mega mat http://www.fatmat.com/bulk/megamat/50.html
I think i shuold use this product because it is fairly thick and reasonably cheap for the price compared to dynamat.
My question is, how many sq ft of the product will i need? im thinking of doing a double layer in the boot and just one layer for the 4 doors.
Comments appreciated, thanks!

Both front doors.
Take the back seat and parcel shelf out and do all the sheet metal there.
Boot floor itself already has a layer.
Next place to do would be inside the boot lid and along the sides of the boot.
A tape measure will be your friend.

Gerry

cheers mate,

I have just realised that all those websites are american and most of them do not shit to australia, and those that do add an exrta $80 dollars for shipping so if anybody new of any good sound deadening brand that ships to australia or a an australian website that sells them, could they please post a link

Thanks

Ryda.com.au sell audio gear online at reasonable prices.

You get what you pay for with sound deadening. Dynamat is basically the default sound deadening product. I would be cautious of anything that was significantly cheaper.

The larger the surface area, the more sound deaning you should apply. Something with lots of welds and bends won't flex as much as a larger flat piece. I found that the rear quarter panels side panels (eg the panel around the fuel filler) vibrated the worst. Covering the *entire* boot with sound deadening is going to be stupidly expensive so apply it smartly. Also, I would skip the rear doors (no speakers in there) and do the parcel shelf (from the cabin side).

While you're deadening the front doors, it might be a good opportunity to block the service holes in the doors. Have a search (both on AMC and the interwebs) and see if it's worth your while.

First of all if you are planning on using the "Fatmat" do not use it on curved areas as it isnt as sticky as you think, and it likes to come off with heat, ensure you clean every surface with Wax & Grease Remover, apply it and roll it out so there are absolutely no air bubbles, this will ensure success of fatmat, same rule applies for dynamat but its alot more forgiving. Also in no way is fat mat thicker than dynamat, they are about on par.

Edit: After I posted this I saw that you asked for a recommendation on deadner, I do not go past Dynamat or Stinger Roadkill.

RV has covered it well, flat surfaces require more attention, I just recently did a VY Commodore and using it properly I did the outerskin of both doors with a Trunk Kit of Dynamat, the innerskin (closest to you when you shut the door) have decent sized holes. Clean this skin, tape over the holes with duct tape and then rest a 3mm/6mm piece of MDF over the tape (in the shape of the hole of course) and then tape over that. This will ensure the outerskin and inner skin are deadened properly with no real wastage of matting. Also if you wanna take the lock and handle rods out of the car and wrap both of them in some tape this will reduce any vibrations that will come from them once refitted.
Also you may ask why do I not recommend Fatmat? See the reflection of the glass.
http://img502.imageshack.us/img502/9476/dsc00004co.jpg (http://imageshack.us/photo/my-images/502/dsc00004co.jpg/)

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Now as for the boot forget a double layer, Matting is designer purely to add weight and in a Magna you will see the thinnest pieces of a boot lid are about 4-5 Triangles between the bracing, a single layer on these would suffice and then you will wedge something between the point of contact for the framing and bootlid, this can be done with foam, or using sikaflex to remove any movement by making this one piece.