we add amps all day longto factory HU while keeping the bose. You can use a hi/lo converter coming off the back side of the bose amp and it will provide enough signal to work. If you were using a amp and couldn't get it to work I would look futher into the install. I'm thinking he tapped the wrong wires.You haveto grab these wires under the center console or in the kick panels heading towards the speakers. Also look into a peripheral electronics SVEN2 (2 channel) or SVEN4 (4 channel), this is what we use.

 

Thank so much guys I will give it a shot.

 

also Peripheral just released a sevn4 that accepts a factory plug n play harness for the 07 gm's. This plugs in behind the factory radio and provides a 4 channel output.

 

i think from what jonny said that they got the signal from the back of the unit ,for sire they got the wrong connection. cheapest and fastest way to go is like e said under the console there is a connector with only four wires,tap into those and it will work for sure i did my first time before i got my aftermarket h/u.and the line driver will do wonders for you're system one of the bets investments you can make and very affordable. i believe Phoenix gold has one of the most commonly used.