Don't overlook the fact that EI also contains a wetting agent, which, of course, can always be added to a home brew, and that there is a difference between ethylene glycol and propylene glycol.
Engine Ice is nothing but deionized water and propylene glycol.
You can obtain the VERY same results by going to the auto store and buying a gallon of propylene glycol (the non-toxic sort of anti-freeze) and a gallon of distilled water.
You will have at that point about 2 gallons of coolant for approx $9.00
OR you can go out and buy Engine Ice that has taken the mixing out of the picture....and spend $70-80 bucks on two gallons....
Let's do the math!
As far as the price, my half-gallon jug is marked at $14, rounded up. That means 2 gallons would have been $56, not $80. Sounds like you shop at the wrong parts store. It is, of course pricier than doing it yourself, but I have enough for both bikes for $5 extra, and I don't really have use for the left-over 1 1/2 gallons of mix.