i recently put an aftermarket hu in the 2003 tl and the factory Bose subwoofer is inop. I was going to replace the factory sub with an aftermarket sub, but looking at the factory Bose sub it says its a 9" subwoofer which ive never seen one aftermarket in a 9". Any help would be appreciated

 

Did you look in the sticky thread at the top of the page? "** DIY / Info / FAQ - For All Acura Models **"

https://acurazine.com/forums/audio-video-electronics-navigation-22/%2A%2Aaudio-video-diy-info-faq-all-models-%2A%2A-299065/

and more specifically inside that thread these two links
# Keeping Factory Sub While Adding a Aftermarket HeadUnit
# Replacing Stock Sub with an Aftermarket Sub