If buying in Canada you're fine. If buying from the US and importing it in, it depends on the manufacturer -- some do, some don't, and some will reimburse you after you pay for work to be done at their cdn dealerships.
Not sure about extended warranties.
In response to your other thread - carcostcanada, get the invoice price and offer a fair # above it. If buying japanese (esp not a mainstream model) expect less haggle room...many of them are running short on supplies.