Check the underside! I have 139k kms on mine (bought new in 2014, Canadian, just like the one you are looking at) and the subframe was rotting away. Here are the major rust areas where I would look if I were you.
- All lower door areas (bottom, where the door skin pinches the frame)
- Rear wheel wells (pull the wheel well liner and look at the plate located under the rear door)
- Pinch welds (hidden by the side skirts)
- Subframe (check for holes, flaking, etc.)
- Lower control arms and knuckles.
- Exhaust (all of it, one of my hangers rusted off)
- Spare wheel well (under the trunk)
- Gas reservoir metal straps
- Rear beam (check mounting bolts, will you be able to service it when the bushings let go ?)
Also, check the condition of the intercooler fins
I would highly, highly, highly suggest putting it on a lift and walking under it with a flashlight and taking at least 10-15 minutes. This will tell you much more about the life of the vehicle than anything else (in my opinion).
4500 CAD is cheap, but a new subframe is not (1300 CAD plus installation). A new exhaust is not. A new set of shocks all around is not. Consider the maintenance items, which could be disproportionately expensive in relation to the cost of the car. Body rust is expensive to fix as well and often overlooked.
Don't forget, you're not buying the car, you're buying the seller. One owner, well serviced, and highway miles are all good things in my book.