If you compare the titles of both threads (the one you linked, and this one), you'll notice that one says PVE shadow priest, and the other says PVP. So no, 'dude' everything he want's to know is NOT in there.
For gems/stat priority, the only diffrence between PVE and PVP shadow is that mastery is going to be rated quite a bit lower, as the ramp up time on shadow orbs is going to be much higher. So INT > Spirit (hitcap) > Haste > Crit > Mastery.
As for spec, it really depends on comp. If you're playing a burst comp in 2s like Frost Mage / Shadow priest, you won't really need the mana talents, so something like this would probably be best.
shadow has a few viable specs depending on length of fight// comp played...and if your the target... favouring ur dots if your the target will ensure bigger uptime on dmg as you will find it harder to get mind blasts/spikes off while kiting...