if my seviper has contrary and uses coil will it have the opposite effect or does it work on just moves?
Contrary: Makes stat changes have an opposite effect
All stat changes are affected, both attacking and non-attacking moves, as well as beneficial and negative. So yes, it would have an opposite effect.
You can see it for yourself here:
It will have the opposite effect,take the classic moody shuckle they always carry shell smash because it will have the opposit effect of -1 atk,spA and spe and +2 def and spD.