I took my 2021 Supra (6/20 date) to the dealer for the factory recall and they are not able to perform task because I changed factory amp to an Audio Plus after market Sub/Amp. I first must remove Audio Plus and reinstall factory amp, then hopefully all goes well with recall. With that being...
On the inside of the door, on the metal part, not the removable panel. Did the same to my BRZ and did not have any issue with water. Thinsulate helped with road noise and tighter bass. After installing Thinsulate a friend said that I must have replaced the amp--I did not.
Looks like a nice setup. I did the same up grade in the doors only and used Focal mid-range-tweeters ( Amazon.com: Focal ES 100 K 4" K2 Power 2-Way Component Speakers : Electronics ). The highs are more pleasant and the mid-bass has more punch. I also have an Audio Plus sub which is very good...
I too have the OEM+ with greater than 50 hour of playing time and the bass tone has greatly improved since first installed. Not want to waiting for the OEM+ mid and tweeter upgrade, I purchased Focal component speakers ES 100K; but I am waiting for the speaker adaptors to arrive from...
I had to wait too, but well worth the wait. Great tone, no drone, and butt meter indicates an nice increase in power through-out the rpm range. Very happy!