I just finished the installation of my front mount today. I didn't use an insert in the new mount. I filled the voids in the mount with windshield urethane.
My biggest problem with the front mount installation was getting the holes enlarged the right amount (so that the old bolts would thread into the original mounting nuts).
My short drive around the block felt really good. I can't wait to get a few more miles on this mod.
This seems like it will ge a good mod.
Mike
1996 SE MTX, Desert Violet (Ford's name for this color blows chunks! I prefer Black Cherry

)
Dunlop Sport 5000s, Ray McNairy's THFix,
Magnecor wires