You should only have to stir when adding your DME/LME to dissolve it.
And that's a loaded question as far as a rolling boil. Yes, you want a boil. As to how "hard" of a boil is totally independent. Me, I find that my efficiency rating goes up the harder I boil. Like right now, I sparged about a 1/2 gallon too much for this batch I am currently brewing(I was kegging a batch so as to use the yeast bed in the carboys for this batch). So, I am boiling harder then normal to try and burn off more liquid to hit my O.G. But, to your original question, yes, a rolling boil.
You Can Give A Man A Fish and Feed Him For a Day, or You Can Teach Him To Fly Fish And Spoil Him For Life
On Deck MaiBock Helles has Wings 5
Primary Bee Cave Brewery Kolsch 15, English IPA
On Tap Camper's Delight Ordinary Bitter