I think there is only 1 raid set, which u can get in BOT/BWD raids...mail set with agi/stam.
And ofcourse Lightning Charged set, which u can get from BH raid, some parts and from vailor vendor.
If u want to get Lightning armor set, my advise is get 4 parts from lightning set (head/chest/shoulders/glove) for set bonus and legs from Sinestra boss (3socets and more stats then Lighning).
Spec...Hmmm...I playing with SV spec, i am happy with that spec. I doing 20-25k dps.
Tried others too, in raids i did less dmg then SV.
If u finde good rotation un can do quite good dps from all specs
But i recommend SV for raids.
Ofcourse gems, enchant and reforgen is differnet for all specs
I will be glad to hear some other opinion
Sorry for my bad english
:D