cool. The only tips I have for you with the M4A3E8 are these:
1) If you use the 2 piece armored exhaust deflector, watch out about alignment. I was careless and caused misalignment that was a PAIN to repair
2) When you add the side skirt attachment points, follow the suggestion in the directions to start from the front and go to the rear. A small part (~1mm) juts out from the back. It's supposed to be there.
There are other 'super detail' items if you wanna go down that rabbit hole. If so, contact me via PM.