Save your money. The snake oil does not work. Ask rfishing. If you head gaskets have been confirmed as being bad and you have no symptoms, it is likely in the early stages and will slowly get worse.
Bah, not that expensive. Got mine fixed for less than $600, but with no labor charges, due to the fact that I was the poor son of a bitch doing them.Do not waste your time with that stuff. I did an extensive review on here with my car and "thermagasket." Seriously it just a learning lesson that I shared with everyone on here. You can probably read about it, if you can find it under search method. Search "Thermogasket", and see how it worked temporarily but then gave out.
Sorry to hear about yet another Norstar engine eating a head gasket. So sad, so expensive...