I am sure I will catch hell for it but honestly I used GreatStuff expanding foam from any Lowes or HD. . . It was cheap and did what I wanted. Just be carefull if you put in any areas like voids where it can expand against the fenders or quarter pannels. If you fill it too much it does have the pressure to push out the quarters. I didnt have that happen to me but have seen it happen on other cars.