If you get this sorted out make a specific post please. I tried the same thing in my 01 Max. Tried to keep the bose head unit and run an amp for all new infinity speakers and my sub, but was gettin engine noise. Rca's and power were seperated on each side of car. Even purchased an Audiocontrol EQX as an interface, but still suffered engine noise. I upgraded my 01 for an 02 max, and have all my stereo equipment sitting in my house. I want to install into my new 02 but want to get it done right. Changing the headunit is not an option! Someone has to have an answer to this problem of running aftermarket amp and speakers with the factory bose headunit.

 

I just bought a ground loop isolator from radio shack.. we will see if it works