This. It's perfectly normal to have normal map look crappy when it's displayed as a diffuse texture, so don't worry if it looks like there is a seam when you apply it as a diffuse map :) When the edges of your mesh are rotated in UV space, there will always different colours at those edges. This is because they are at…
Don't put your normal in your diffuse to look at them, that's a terrible way to debug stuff. Instead put in your Normal slot and see if it looks good, it not, fix you Smoothing, Chamfer edges, etc.