Meguiar's products worked well for me too. I started with their number 17 Clear Plastic Cleaner followed by their number 10 Clear Plastic Polish. Instead of using an electric polisher, I did all the work by hand because I thought that I would be less likely to get the compound on the cloth top that way. The project wasn't especially quick or easy, but the result was better than I had expected. Here, take a look...
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2002 Boxster S Orient Red Metallic / Graphite Gray
https://rx19jones.wixsite.com/a-986-s