Any idea how to get fittings out of aluminum intake?

If you do end up taking a pipe wrench to that nipple,,.. put an appropriate sized bolt into the hole of the nipple,, so it doesn't collapse the fitting, you'll also get a better bite on it, and it's often re-useable after removal..

This works on dipstick tube removal, etc as well

Can you get a deep socket on it,, with a breaker bar?

hope it helps