and please understand that, the guys here that said to use the yeller stuff, WOULD NOT advise that if they thought it would do any sort of damage or corrosion. most if not all probably have it their own cars.

In that video, they fill the cooling system with water from a garden hose, which is a BIG no-no. Using distilled water is just as important as deciding which type of antifreeze to use. The minerals in tap water will slowly accumulate in the radiator core and plug it up.

This is good advice, distilled water will not have dissolved mineral content, so there can be no mineral reaction or accumulations within the radiator and cooling system. However, I just want to point out that mineral build-up is typically likely in a situation where the water supply is being regularly replenished with more mineral-laden water, like in a humidifier, a clothes steam iron, a coffee maker, etc.

Provided that you aren't constantly adding water to your cooling system, I can't imagine the mineral content of one cooling-system-full of any municipal water supply being so mineral-laden that it could actually plug a radiator core, without some additional mineral source. I have never used distilled water in an automobile cooling system, and I have never in my entire life seen a radiator get plugged from tapwater minerals.

Nevertheless, steam irons come with instructions to use distilled water, and if you do use distilled water in your cooling system, you can rest comfortably knowing that you haven't added any unnecessary (and potentially damaging) minerals to your cooling system. So I'm not really disagreeing, it is absolutely good advice, but I think it might also be overkill, I've never had any problem using tapwater. (I put tapwater in my steam iron too, if it ever clogs up I'll either run vinegar or CLR through it, or throw it out and buy a new one. But at the current rate, I think it will probably last longer than I will.)

To add to the above, if you are really concerned about minerals in the water, and don't have any distilled water available, if you have a water softner and use the tap water from in the house, you will get less minerals than what you would from the hose spigot outside, which is typically not softened water.