Not very difficult, if you are careful. I got them for all of my emblems, and I was pretty impressed with the quality and forethought they put into them. I did struggle with the "1500" portion of the hood emblems, they seemed to stretch easily.
A couple of nice things about these guys: They send a few extras on the trickier ones in case you run into trouble - sure took advantage of that! Also, I was able to order two different colors in for the hood emblems, so my "1500" is the same color as my truck, and the "HEMI 5.7" I did in bright orange