Can you post some pictures of these patches or issues you have? I have mine and it seems fine but I also don't have anything of high quality in hand to compare.
And if you took the time to read his step by step guide. He doesnt use the fuse that has constant power. If you did some research and read the dashcam thread youd know that hard wiring a dash cam into a bmw isnt the best idea. That's why he bought an external battery which you plug the camera...
I dont think he installed into the one with constant power as this causes issues for bmws. The camera is plugged into the battery which powers it when the cars off. And the battery is plugged into the fuse that shuts off when car turns off. So itll only charge when the car is running.
i wouldn't. like @XtremeMaC said that the manual states not to. don't need to give toyota a reason to void my warranty by going to a non certified place.
i don't think that would apply for the supra. no one is going out of their way for a 50k+ sports car as a daily driver. i see corollas and hybrids going up though.