The car actually has a few common problems. Though the engine does last very long. Over 200k. But lots of preventative maintenance is needed.

Here are the common problems:
Starter goes bad around 70k miles.
Ignition Switch goes bad if your key is Vag 15.7 heavy from attaching a key chain to it.
Vacuum leaks (Common with all 10+ year old cars)
MAF Sensor
Water Pump
RMS (If you have an oil leak, this is probably the problem. Easy fix. Just a sealant.)
IMS ($2000-3000 repair if you catch it early, $20,000 repair if you catch it too late.)

All of these usually go bad anywhere from 60,000-100,000 miles except the IMS/RMS.

The IMS and RMS can happen at any mileage without warning. The best preventative maintenance is to change your oil every 3000 miles instead of Porsche's recommended 10,000 mile interval. If you find metal shards in your oil filter when changing the oil. Get it towed to a Porsche mechanic immediately for an IMS replacement.

For me, it has been a great and reliable car. I got it cheap because it had some problems. So when I bought it, I fixed the water pump, I fixed the inner tie rod, I replaced the rear plastic window, and I fixed the rough idle by cleaning the throttle body and replaced a few light bulbs. All together costing $1000 of repairs and maintenance within 1.5 years of ownership. That is not too bad for a 12 year old car.

In case you do not know, putting the top down GM Tech 2 when it is colder than 75 degrees Fahrenheit will crack the rear plastic window. Only use the top in summer when it is hot.

Also, oil changes at regular mechanics cost $80-120, while they cost $185 at the Porsche dealership.

Alignment. $80-100 at regular mechanic vs $145 at Porsche dealer.