I have had a very good experience buying vehicles from Carmax including a Boxster. You can go to
www.carmax.com and seach CA inventory etc. They give a 30 day warranty on all vehicles and offer a competitive extended, not sure if it works in Canada but it may? There was some peace of mind for me in buying the car then taking it for an inspection knowing the complete car was covered. I would say its probably the next best alternative to buying form a Porsche dealer. Most of the cars I found around So Cal outside of Porsche, Carmax and privates were lease returns and they did not look to good, I was looking at 01 to 03's and ended up buying an 02 with 32,000 miles. Good luck.