i used 80 square feet so far and i have a few more panel/trims left to do. I would highly suggest you get 100 sq/ft. all I did with 50 square feet were my four doors and tailgate.

 

used 80 square feet to do 2 doors, rear shelf and trunklid..........this was before I knew better.

 

im using b-quiet extreme. used 100sq feet and need 200 more. got 4 doors outer skin inner door skin and plastic pannel. and about 8sq feet on trunk hatch.. i still need to do 1 more layer on the door inner skin. rear side walls. roof. floor. and ya put in as much as u can afford and add some MLV if u want for a more quiet ride.