Quote Originally Posted by ADarklore View Post
However, is it even possible to use Samurai or even Red Mage in lower level MSQ dungeons? I figure I could run the dungeon with SAM/RDM and then switch back to another class to turn in the quest for the XP. But, I'm not sure if you could use higher level class with lower level MSQ quests or not? I do understand that higher level skills will be greyed out for lower content, but would be nice to know if it were possible to even do.
As others have already said, you can take your high-leveled jobs into low-level dungeons but they are synched down and only have a few skills available. Have a look through your skill descriptions in the Actions and Traits menu - it will list the level at which you "learned" these abilities (even though you really got them all instantly at Lv50). Level synch for dungeons gives you access to your skills based on these levels.

As for handing in the quests, all the game checks is whether your current level is equal to or higher than the quest level - so you can do this not just with another battle class, but actually with crafting or gathering classes as well! In ARR anyway. They 'fixed' that for Heavensward.