Originally Posted by
Paf
What Radux said is correct, though. If you have a set of both restoration and elemental, you can (before the pull) equip the restoration set, use Spiritwalker's Grace, switch back into the elemental set. You will retain the 30% haste buff for its duration. Normally, if you did this with any other piece of gear (sans Moonwell Chalice pre-patch), the buff would be fizzled and removed. Also, if the gear you replaced the cheating gear with was cooldown based, you'd have to wait the duration on the freshly equipped gear. This can be done with even the LFR restoration set as the set bonus does not scale with higher levels of itself.
Just think of it as pre-potting with four pieces of gear.