I have the LTZ model with the bose system but want to add 2 jl W2's under the backseat. Is it possible to hook up a system with a stock head unit? How hard would it be, i heard the LTZ has an extra amp or is this bogus? Any information or pics of installs would be appreciated

I have done it. I added a 10" under the back seat. you need a Scosche SLC4 line out adapter. that will give you the line out to go to your own after market amp for your sub. I will take pix tomorrow to add.

Thanks man ill look into that piece

My boss at the last company i worked at had 2 12's under his backseat with the factory headunit, sounded good.