In terms of sound deadening, I found it most useful in the doors and the parcel shelf. I had my whole floor deadened, and honestly, there were little to no effect. Weight definately adds up, for a mid sized sedan, if you do up all 4 doors, the floor, parcel shelf, and the whole boot area, you are looking at approximately 50Kg of dead weight. That will effect yout FC.
But kkyak bro, your diy skill and effort deserves praise! Good Work man!
Sorry for bringing this up. But just some info to share after doing qutie some dampening work on different cars.
Hm... maybe priority wise, it should be doors first(which is most important), rear parcel shelf, then the roof and wheel wells, then the firewall, and if you felt money to spend, the floor and finally the trunk floor and walls. I would actually recommend something that cuts down noise instead for the floors(including the trunk floor), like those fiberglass or felt sheets(same kind of spongish material under the main car carpet on all cars).
Found that out when i stripped one of my cars clean of any carpetting and slowly adding piece by piece back up to know which parts matters the most.
