2014 gmc sierra, amplifier

Has anyone installed an amp in a 2014 Sierra? The Truck does have Bose and is a Crewcab. I stopped by the local audio shop and the dude there sounded like an idiot and was trying to sell me new subs/amp instead of help me out on the stuff I actually needed. I know I will need some kind of Interface to get the signal from the amp. He told me that I would need a convertor that ignored the factory stereo's signal to lower the bass as the truck moves faster. This true? Thanks for the help.

What are you amplifing? Are you just adding subs or are you redoing the entire system?

I guess I should have been more specific. I will be installing a JL Amp with hi/lo I puts and two JL Shallow Mount subs. I will not be touching any of the other speakers or HU. I know the Bose amp is located behind the rear seat. Just need wiring info and the type of convertor needed.

We have not seen a 14 with bose yet. On the non bose vehicles the wiring colors are not what they were on previous models. If there is a factory sub, you will have to tap those wires. If you want a control knob use a Pac-Audio.com LC-2. If your amp has a control knob that you can mount under the dash, use a Pac SNi-15. In years past the factory sub wires were larger gauge than the other speaker wires. If you find 4 larger wires at the amp, there is a good chance those are the sub wires.