In Canada we would only pay a 5% tax on the difference between the used car and the new car price. There is a provincial sales tax as well depending on where you live, again on the difference. I agree with enigma's math, its spot on. 25,000km per year is really not much over the average, however if you keep the edge to the end of the finance term on either one, both vehicles will have enough mileage on them to make the resale value poor. The difference in payments is $30 a month plus one more year. If ou can afford that I would go with the 15 because of factory warranty and it has the options you want. Let us know what you decide.