I have always had a coating placed over the clear bra, I have had this done on several vehicles with no ill effects, though I cannot testify to this long term as I don't keep my cars for longer than 5 years. After several years my thinking has changed somewhat on this topic, allow me to explain. I've always had paint correction performed prior to the installation of clear bra. The condition of your paint really sets up the foundation for the "wow" factor, the coating is icing on the cake. Paint correction, even on a white car will make it "pop". On most new vehicles, including Porsche, the surface condition of the paint is terrible (IMHO). My current 911 took 9 hours to correct, so my advice here is to ensure that you have a reputable detailer perform the work, it's labor intensive and you want an honest job done. I have used the same detailer for many, many years and he does superb work. I am a fan of Modesta coatings - FYI. When you see your vehicle in the showroom, it looks perfect, no doubt, but get it under the detailer's lights and you will see the defects clearly, even on a brand new Ferrari. From here on out my protocol is going to be paint correction followed by clear bra, and no more coatings. A good coating is very expensive, and I don't want to spend the money on it anymore. IMHO, paint correction and clear bra is plenty protection. There is one deviation I will make here - the wheels. Whether you have OEM wheels or aftermarket, these are a significant investment. My detailer removes the wheels from the car and corrects the surface, inside and out, using a rotary machine polisher - this is a more aggressive approach for a painted surface vs. a random orbiter (used on the painted surfaces of the car). Once the wheels are corrected, he applies a coating to them, this not only gives you a "wow" factor, but also makes cleaning your wheels a lot easier - I use Wheel Woolies and Sonax Wheel Cleaner. I will always have my wheels corrected and coated. Now on to the clear bra - the installer is key, you could select the most expensive clear bra and it wouldn't matter one whit if the installer is no good, believe me when I tell you this as I had one bad experience any years ago with this, and it sucks. You simply can't see clear bra if it is installed correctly, yes, you will know it's there, but a superb installation is hardly recognizable. In closing, I will tell you that I used to do all of the above myself, I watched tutorials on the topic, read books on the subject, purchased all of the equipment and materials, and found it to be excellent therapy. I am unable to do this anymore due to significant athletic injuries over the years catching up with me, it's a very physical process and very detail oriented - excuse the pun! If you want to educate yourself, I would recommend watching Esoteric Detailing Videos on YouTube. These guys do excellent work, and have a stellar reputation, their videos demonstrate clearly how a vehicle is corrected and clear bra'd in the appropriate manner. Lastly, products in the detailing industry have improved greatly over the last 10 years, it's almost unbelievable just how steep the trajectory of improvement has been, it's really benefitted us, the end user immeasurably!