....This time I was told that the brakes are meant for hard driving.....
This is a common story. Here's the question that immediately comes to my mind. How do those folks explain the thousands of Porsche's and other high performance cars out there, that are not driven hard, and which don't have squealing brakes? Given that logic gap, the story is likely more myth than fact.
Here is what wikipedia has to say on the subject of disc brakes....under the sub-heading of Brake Squeal:
"Sometimes a loud noise or high pitched squeal occurs when the brakes are applied. Most brake squeal is produced by vibration (resonance instability) of the brake components, especially the pads and discs (known as force-coupled excitation). This type of squeal should not negatively affect brake stopping performance. Techniques include adding chamfer pads to the contact points between caliper pistons and the pads, the bonding insulators (damping material) to pad backplate, the brake shims between the brake pad and pistons, etc. All should be coated with an extremely high temperature, high solids lubricant to help reduce annoying squeal. This allows the metal to metal parts to move independently of each other and thereby eliminate the buildup of energy that can create a frequency that is heard as brake squeal, groan, or growl. Cold weather combined with high early-morning humidity (dew) often worsens brake squeal, although the squeal generally stops when the lining reaches regular operating temperatures.
Dust on the brakes may also cause squeal and commercial brake cleaning products are designed to remove dirt and other contaminants.
Some lining wear indicators, located either as a semi-metallic layer within the brake pad material or with an external "sensor", are also designed to squeal when the lining is due for replacement. The typical external sensor is fundamentally different from the noises described above (when the brakes are applied) because the wear sensor noise typically occurs when the brakes are not used."
https://en.wikipedia.org/wiki/Disc_brake
Bottom line; fixing brake squeal requires disassembly, cleaning, and lubrication of the metal-to-metal contact points on the calipers. I was taught this technique nearly 40 years ago, and have found it to be 100% successful on the cars I've worked on.
If your current dealership cannot solve the issue for you, take the car elsewhere. Also, be sure to give your previous dealership's service department an unsatisfactory performance rating on their customer satisfaction survey (if you get one).
You may ultimately need to find a good independent Porsche shop to fix it, unfortunately. Persistence is the key. Best of luck to you. It's very frustrating for you, I'm am sure.
