First used purchase planned. Purchase advice requested.

Hello! I have never bought a used car before, am therefore inexperienced and hope that I get a few tips. Specifically I have the following offer in mind: Porsche Cayenne Turbo (9PA), first registration 2007, 180,000 KM, complete service booklet, accident-free, 2 previous owners, 17,000€. Of what I have read so far about purchase advice here, it tends to be discouraged from such offers, but I always wonder why? The price sounds quite attractive at first. he has managed 180,000 km, one would have to have already a lot of bad luck, that exactly immediately after purchase motor/gear goes in or on what are the recommendations rather not to buy? What exactly are the concerns? Thanks and LG, flipsns.