The way I filtered out this is....
If you are running a in-line 6 (low rev. motor), no worry. Even the manufacturer of the additive says it is not needed. On the other hand, if you are running a V-8 (higher rev. motor), it will be a problem WAY OUT in the future. I rebuilt a 283 V-8 and had the hardened seats put in at that time. I don't think it is worth a head rebuild just to do seats.
Drive it and put in additive if it gives you peace of mind, its not much $$$$
Others will chime in.....
Buddy
