Correction,
Je viens de voir la réponse:
OKAY, for everyone getting a Neck Mismatch, YOU HAVE THE WRONG Navatsea Resolution.
Get The High Resolution ones (Vanilla skin texture v1_8 shaved MAIN FILE.) that are found on her page. The ones Packages with The Muscle Texture Changer are of the a Lower Resolution, and that what causes the mismatch. By Getting the High Resolution one found on the Old Version section and replacing the the textures inside (Which doesn't ruin the Muscle Effect.) The seams WILL Disappear
Also most people seem to be complaining about Neckseams, without realizing that there isn't any. The problem is that Skyrim has a crap lighting engine, which put less emphasis on the face and NECK. Because of this when you're not looking up with your females, you can see a seam that shouldn't be there. Most ENB's and Lighting Mods FIX this however.