As far as I know with Boomkins: You have to spec differently PvP to PvE on account of talents that are more useful in one over the other. (ie. Typhoon: Useless and frustrating (for the tank) in a PvE raid... pushback+ tank = dead you; PvP: pushback + you = happy and alive!)
There are some really good boomkin dedicated sites that you should go have a look at as well, they go into great detail about dps and specs and such. Can't remember the name of it off hand, but google should yield the answer.