I agree, of all the mods I've done over the years, getting an alternator that will charge solid at idle is the best thing for drivability. not just motors, but the injectors themselves fire much more more stable at the correct voltage. there's a table in most ecm's for the voltage vs time offsets. but those spec where from the injector manufacturer when new. 150k miles later. if you can keep the voltage up at idle, there's less chasing trims for it all to do. not as huge on stock trucks, but can be a very big deal in the aftermarket world.
if you're curious about it find a good deal, seems like a 100$ well spent.
instead of all the big 3 kits, I like to move the electric cooling fan load straight from the relay to the back of the alternator. on high these modern fans can pull crazy amps and at higher voltage without the drop from running thru all the factory harness and fusible links. the motors are much happier and so is the factory harness.
I use the slow blow jcase fuses on each fan.
