Hi John
I have just been through this with my GT3. Unfortunately, I left it a little late to decide to ditch my Cup2’s for PS4S’s once I saw the weather forecast for my visit to Millbrook.
My first choice a Porsche indi recommended on here, had a U/S wheel balancer. I managed to get a one day discount of 25% off the Michelins, but had to use one of their fitters. I did due diligence, and phoned to make sure they had experience of the wheels, which they assured me they had.
The tool key to remove them is in a plastic tub near the battery, under the plastic cover. The main problem is the required torque to tighten them. The instruction manual gives the details required.
I was horrified when I arrived at the fitters to find no one had any experience . Thankfully, I had watched a couple of YouTube videos to see the important points, a number of points are very different to normal wheels, eg the wheels must be off the ground when torque is applied. I stood over the guy and told him what Porsche recommends, he wasn’t that interested to learn something new!
If the garage has the wrench with sufficient torque, and you are prepared to stand over them it can be done.
Good luck.