Hey, sorry, just noticed your message now. To answer your questions:
1. There should not be any state sales tax on anything you buy, in any state, so long as it's going to be registered to a Canadian address. Basically, pay for the car, get the title signed over, and leave. If you're buying from a dealer, they should be aware of this.
2. At the border, you'll have to pay sales tax, duty (6.1%) and a/c tax ($100). Personally, I do commercial imports under our dealer license (I run a leasing company) so we pay the full HST at the border. I believe on a private import you pay GST at the border and PST at the MTO office when you register it, but I could be wrong about that.
If you have any more questions, feel free to ask - best to send a pm, so I get an email notification about it.
Good luck!
