well to be exact, you gain more Performance than just the weight of the AC because you'll also remove a pulley (the AC motor) that the crank will have to spin... it's the same effect as getting an aftermarket pulley to reduce the amount of weight the crank has to spin... but better because you're actually eliminating 1 pulley instead of making it lighter.
as i mentioned above it does not move unless you turn it on
Um, I don't think so.
The AC Condenser pulley runs on the serpentine belt, so it runs all the time, it just has to run harder when it's turned on. It's the pulley directly under the alternator.
If you want to remove it to save weight, then go for it.
Otherwise, you can just buy a smaller belt and bypass the pulley all together. It's been done before.
And yeah, it's more like 45 pounds, not 5.