Hello,

I had my factory deck done up with the bluetooth mod which is really good. Now I'd like to add a little bass to the system but don't want to hack up the bose setup. I am thinking of getting a JL 8 or 10" micro powered sub. Small and good bass from what I hear, but I need to tap a high level line somewhere in the back that is full signal L/R. Can i do this off the rear shelf speakers post bose amp?

 

Not helpful, but a good mono signal for pure low end is the rear deck offset center speaker. I don't know that it's purely mono per se or if 1990's MB decided just one rear channel would be enough for competent low end.

Point being that if you just want to take the bass response you're getting now and amplify it, just use the channel on the inner rear deck woofer.