PvM VS PvP?

Ghazi - Heavens Tear

I am currently following the stickys to create a pure Tank Barb. If I wanted to change from PvM to PvP, what should I do. Add more dexterity? In replace to what? Strength, I doubt it, Vitality, I wouldn't see why. Or do the attrabutes stay the same and the skills differ? I know for a PvP Barb you should choose Demon path but is that all the difference in PvP and PvM? Can someone help me out?