Talked to my installer this weekend, and he recommends not using my line driver. He doesn't like using extra components that might introduce noise into the system.

I think el_duderino posted that the stock voltage from the Bose HU was like 2-4 volts. Wouldn't it be best to have my component amp seeing maximum voltage with the use of my line driver?

 

The output is low enough from the HU to connect directly to an amp (I think max was measured to be 2.2V at max HU volume). The voltage is also high enough that you should get decent volume range. There is not much point of amplifying the signal before hitting the amplifier.

 

I would TRY it without the line driver.

However, in cars whose OEM HUs had lower voltage than the G's, I've had issues where if I kept the amp gain low, I didn't have enough volume, and if I turned the amp gain higher, I got oenough volume but then could hear engine noise that I couldn't hear before.

Raising the gain raises the noise floor, effectively.

Installers tend to want to avoid things that might give them trouble. SO try it without it. But if you can't get enough volume, then you might need one, or if you have noise at useful gain settings and no noise at gain settings that are too low, you might need one - BUT - your line driver has to take balanced in!