My understanding is that you really need mass loaded vinyl to do a good job. You need some sort of foam to isolate the mass loaded vinyl and a small amount (25% coverage) of sound deadening on the sheet metal to dampen the vibrations. There isn't much room behind the door panels, so if your foam is too thick, you will have problems putting the panels back on.
What is the size of your bank? As KW_DA said, you will need to get something like Noico or Kilmat, etc. I just did my doors with Noico 80 mil sound deadening with Noico Red 150 isolation materials. The front doors are a PITA. Well, all doors are a major PITA. On the front, at least, you can remove a bunch of garbage that was put on at the factory. On all doors, it is almost impossible to get to bare sheetmetal. There are some pockets where you can sneak some material through. Mazda bolted on a huge plastic part to which all the cabling and window motor is attached. Not worth the time to remove it. Also, especially with regards to the rear doors and rear trunk panels, the fit between them and the sheetmetal is very tight. On the rear doors I only applied 80 mil and 150 Red to the door card. The trunk is probably the simplest of all things to do. I have not done the floors or ceiling yet. However, I do not know how much it will all help. The engine is just loud and glass is way too thin. The best thing you can do is get nice (and quiet) tires and crank up the volume
P.S. When removing the door panels, make sure you get the right tool for removing the white plastic clips that attach them to the sheetmetal. You can always get replacements on Amazon, but without the "metal fork" tool, they snap and break very easy. This tool is dirt cheap on Amazon, so definately get it.