Thanks for all the quick replies!
I'd like to clarify something: these 2 cars are not at the same dealership.
It's not like one dealership told me it cost them 4000$ to CPO the car. In fact they told me it cost them about 1700$ to CPO the car.
It's just that another dealership has a great price on a 2000 Boxster S at 19 000$ but it's not CPO'd.
As for the aftermarket warranties, WarrantyDirect does not apply in Quebec.
A lot of aftermarket warranties you guys have in the USA don't apply in Quebec...