Buying a used porsche cayenne, need advice!

Hi fellow porsche cayenne owners.

I'm currently looking around on ebay and other online car websites in Canada to find a used 2008+ Porsche Cayenne S. So far i've been about to find ones around $32k (CAD) with 78km mileage.

Now, my biggest concern right now is the maintenance that I will have to pay per year. I just want to get a rough gage on how much you guys usually spend (yes, i realize that the way the previous owner drove the car is a huge factor) in a year for maintenance. Is it practical to go to the dealership or an independent mechanic?

Also, I would love to hear about your stories about buying a used car (especially online)

Thanks in advance