Shadowpries Raid buffsFollow

I play (only) my mage on WoW, and noob out on all other classes-info. ^^

But, what I would like to know is: shadowpriest can supply the raid with manaregen? If thats true, what's that spell/ability called?

And, like a mage can do Scorch (x5) to give all dps-casters a 5% critbuff on a mob. I know a Warlock (shodowbolt-spec?) can do that too. I read somewhere that a Shadowpriest has also a kind of +crit buff on a boss? If that's true, what's that spell/ability called?

The reason I ask, is because I don't want to use my Glyph of Scorch (wich apply's 5x scorch in a single cast in sted of 5 x cast) but if no other in my raid is doing that I gotta keep that scorch up so all caster benefit.

I read this back, and it looks bit messy, but I am sure some skilled priest can provide me with some information :)

Shadow priests are the kind of thing that it's nice to have one or maybe two in your raid, but you don't really gain anything from stacking more than that.