Well, lets look at that difference for a minute. $160 US is now $192 Canadian with current exchange. Add taxes and duty you are around $120 to $130, depending on how customs want to deal with it. Then shipping, $25 - $ 30 isn't out of the realm of possibilty. So say you can get it here for $260 shipped, seems reasonable.
Now, Frontier is $289 + GST, so $303.45, for that $40, for me, I like the piece of mind that I can send it back if it doesn't work, or if there is a problem, and know it will be taken care of. You are right though, buying off EBAY is cheaper, but............