I never paid any Florida tax. I paid for the car at the guys bank. I drove home with his plates, title and a notarized bill of sale. Showed the US border people the bill of sale and the title, they did an X ray on the car. They did not look at the VIN either.
Paid GST at the Canadian border after filling in some paperwork.
I got a temporary tag and plate at the DMV, got a emissions test and roadworthy test. Got the sticker for my plates and paid PST. Sent in the RIV papers and got a RIV sticky for the car.
Maybe they tightened the process up, I think I sent a copy of the title to the US border 3 days before crossing back over.
Ditto for me. I bought mine from a dealer in Michigan. No taxes due or paid because the title was not transferred to my name - only signed over with a bill of sale. Dealer provided a transport sticker - no plates. And you do need to advise the border about three days in advance to allow them time to check to SN. The dealer brought the car through Detroit/Windsor for me and I handled the Canadian side customs. Everything about how to do this is online, and it's amazingly simple when you have the proper paperwork and the border has experience in this. You must pay the Federal portion of the HST at the border, and the provincial portion when you get it home and license it. The DMV can be a problem here because they don't always know what's going on, so keep your receipts as proof.