Does the Bose system equalize the sound from the HU or from the amp? I ask this because I'm looking for the best way to bypass the system eq. I want to install my own eq. The only think I'm keeping is the factory HU.

Also, in order to convert the high level signals, I'm looking into the Audiolink PD-4. However, I read somewhere that using line level converters for the interior speakers, as oppossed to subwoofers, will give a distorted, harsh sound. What do you think?