I think you should do some more research Larry.
The cam in the 3.0 (intake only) is different from the 3.2. The 3.2 needs a different cam timing and lift to provide more lower rpm torque, which is required for the auto tranny vehicle to respond well. So, if you put 3.0 intake cams in a 3.2 atx car, you will decrease performance. If you put 3.0 cams in a 3.2 in a mtx car, then you will indeed get more power and torque and increased performance (at the expense of somewhat diminished gas mileage).
The heads are functionally the same, but the front head is in fact different between the 3.0 and 3.2, because the alternator mounts differently on the two versions of the engine. So, the only reason to swap heads is if you want to put the 2-belt accessory drive on the 3.2 engine, or the single belt accessory drive on the 3.0. You need to be aware that doing so also requires changing the front motor mount, as that is tied into the whole front bracket which is part of how the accessories mount.
Also, head gaskets are hard to find, there appears only to be one manufacturer still making them and there have been reported failures with that brand of head gasket, so removing heads is not something to be undertaken on a whim. And while the aluminum heads are certainly lighter than iron ones, they are still heavy and getting that rear head off the engine in the car is not a trivial task.
So, swapping heads/cams for a performance improvement on a 3.2 atx car is a waste of time and money, because it will actually decrease performance.