Sounds like you are trying to learn everything about each product before you make a decision between going with GC or OCP. I'd suggest to go with OCP. That is what is on our brand new car.
And everything else is also coated on the inside
I am pretty sure you are intelligent enough to figure that one out. Do you get powertrain warranty if you do the maintenance? Of course not. Same with exterior protection. No matter how much you train/educate the customer, for most, how they actually treat the finish is very different from how the paint "should" be maintained. Even with all the abuse that most cars go through, Optimum is confident enough that for 5 years the coating will hold up enough to their standards. Either way, (unless you have the coating compounded off) the coating is on the finish. You did read Dr G's post above right?
Don't forget to post pictures of your freshly coated car!!!

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