GST is applied at the border or where you clear customs. When I trailered my plane home, customs took care of the GST right away with my credit card. Then interviewed me for over 20 minutes about the airplane, asking many times if I had another bill of sale with a higher price on it! Only after they searched me and I showed them the website of the company that I bought it from, did they let me go.
They didn't even look at the actual plane!
