I’m glad it’s not just me that has noticed this. I clean the Supra and my GTI windshields the same. The GTI always looks great while the Supra looks like garbage. It’s so strange.
Xpel did have a kit for under the doors and to do the sections behind the rear wheels. I have both of those on my car as well as a lot of other areas covered.
If it’s with Sport mode on, it’s the fake engine noise. Turning that off makes the sound system tons better. Also, try adjusting the equalizer until you find something you like. The system needs a lot of tuning to make it sound decent.