Believe me I thought of that but what do I do with the wheels and tires that I drove down with ? I have a car hauler and thought about hauling the car to the U.S and doing a quick parking lot switcheroo with the new set and throw the old set in the van. In all seriousness when I spoke to Canada Customs on the phone they advised me to have the wheels and tires shipped directly to Canada so I only pay the duty fees which is 7% on top of Ontario tax-HST (13%) because they feel I may get dinged with duty from both the U.S when I pick them up and then again in Canada when I bring them across. I only reason I don't want to let FedEx bring them directly to Canada is because I'm afraid they will have a hay day with brokerage fees.
When I spoke to U.S Customs they said that their would be no duty fees but I'm not completely convinced of that.
'PeteX1/9
Bring the tires in your van. Tell the customs guy those are your autocross tires. Your pretty tires are on the X now as there was a car show after the autocross.