Stereo & Electronics - where to hook up a line output converter on a 04 ext

hey guys im geting all my stereo stuff together to install in my 04 escalade ext and im just waiting on my box to get in but i was wondering where to hook up the line level for the amp.
my truck has the bose in it.
thanks guys

you pull out the cup holders and down there on the right hand side is a bunch of wires, there are 2 sets of leads twisted together (not ran straight) those are your factory sub wires.....tap all 4 of those wires to your line out and you will get the best signal....if you tap the rear speakers it wont sound good.

ok thanks but where is my factory sub at?

its in the lower front part of the console facing the firewall ( in front of the cup holders) but you can tag the wires underneath the cupholders.