There aftermarket amp to the signal comeing straight from the stock head unit? In other words bypassing the bose amp. Did you use a line driver to boost the volts or does it sound ok?

 

I tried it that way w/o a "line driver" but it was no different from using the LOCs (the output was a little weaker but cleaner)

 

Is it weaker because its lower in volts comeing from the head unit??? If so There is this thing called a pre amp line driver...I think it would take the signal from the head unit and increase the volts and them make the out put on the amp stronger. Check it out it's called the overdrive pre-amp line driver. http://www.audiocontrol.com/caraudio.htm
Would this work?

 

running the signal from the head unit to an aftermarket amp (bypassing the bose amp) does work. You run the low level signal from the deck to the high level inputs on your amp... i tried it once with a line output converter and for some reason it did not work as well, but if your amp has HIGH inputs, do it that way. The only other way to do it is to run the outputs of the bose amp to the high inputs on your amp or to a LOC, any other way is a waste of time and it will not give you much better sound.

 

I hooked my directly into the line level inputs on my amp without a line driver, and I get great sound. I have a 300w amp pushing a single 12" and don't even have the gain on the amp turned up all the way. More than enough for the rest of the stock system.