We are agreeing on the same thing, but your too stubborn to see it.
Injectors have a price
Dual pumps have a price
Tunes have a price
Adding pulleys, also having a price, is cheaper to do at one time. So EVERYONE else does it at once.
Doing Injectors, pumps, tune and then coming back later to add pulleys and RETUNE seems pointless. That's where the "free hp" note comes from. Saving the hundreds of dollars on a retune. Not that any of this is cheap or free. I'd surely take the extra 50 hp at the expense of the pulley since the initial tune cost the same amount as a non pullied tune.
So the point is... go ahead and add pulleys if your doing ALL OF THE OTHER MODS. You'll gain multiple lbs of boost and make your car quicker. Which is the purpose, I suppose.