It's not on a Speedster, but I did a DIY ceramic coating on my 996 in November '19.
There are several kits out there, and I spent some time in a few detailing groups before I pulled the trigger on the process, and the product. I ended up going with the CQuartz UK kit (available on Amazon), and I've been really happy with it. It beads as well now as it did when I first applied it (and I've kept up with the maintenance top-up applications, super easy to do, the same time/effort you'd spend on spraying and wiping down with a quick detailer).
Your success or failure with a ceramic coating will come down to prep. Seriously. 95% of the time I spent on the car was not on the coating application itself, but it was on the paint correction leading up to it. I had a bit of oxidation on the roof of the car, some decent swirls on the clear surface, and a handful of surface scratches, but all of those came out with patience and time. Here was my process:
1. Two-bucket wash of the entire car.
2. Clay bar over all of the paint surfaces.
3. Two-part compound and polish with a dual action 6" polisher. I used the Meguiar's M105/205 combination, with an orange pad with the M105 compound, black polish pad with the M205 polish.
4. Quick detailer spray wipe-down to remove any polish residue.
5. Alcohol wipe of the paint surfaces.
6. Two coat application of the ceramic coating (and then the top-off application).
I'd say the most time I spent for the whole process was step #3, to make sure I addressed all of the oxidation, swirling, and surface scratches. With a car that had very good paint to begin with, I might skip the compound step, but would still do the clay bar and polish step.
Anyway, it came out really, really well. I've been using the top-off spray every other wash of the car, and the coating has been very consistent in beading and finish. And, even though the paint seemed perfect after the polish, the luster of the color (Porsche Guard's Red) was noticeably better after the coating application.
This video really helped me with the process (and regardless of the coating you choose, the process should be roughly the same):
https://www.youtube.com/watch?v=byKcYsEyWGk
Good luck!
