I've been browsing through topics for awhile now, and can't quite find a concrete answer.

I'm still using the Bose speakers that came with my car, but i have a metra it and aftermarket HU putting out alot more power to them and also running a seperate amp and sub off of the HU ( only 400w sub and 780w amp, didn't buy my big stuff yet, just ran the lines)

The bose speakers are INSANELY better when the stock HU gets replaced, but i often get a rattle from my doors, especially drivers side, mainly coming from the mirror, tweeter area, or the upper part of the door. Is my best bet to just dynamat the door and the trunk while im at it? I have never used dynamat and don't want to screw anything up, haha

 

Dynamat is not going to help with your rattle. Unless you happen to place it exactly where the two offending panels are vibrating together.

Your best bet is to go hunt down exactly what is making the noise, and stop it.

 

Try this...

https://www.rx8club.com/series-i-trouble-shooting-95/rattle-noises-coming-l-f-mirror-78286/

 

+1
I did this exact mod and it solved the problem you're having.

 

will try this and let youll know how it goes