2011 Chevy Malibu Factory Amp/Stereo

Hello everyone, this is my first time on this forum. I have a 2011 Chevy Malibu LT with a factory amp in the trunk. My goal is to use my stock radio which has XM radio & On Star run (2) LOC's (1) to my high amp for door speakers & rear deck 6x9's and another LOC to my sub amp without my radio locking up on me & having to return to the dealer, not loosing any door chimes, Onstar or XM capabilities. I have located the factory amp in the trunk. Should I splice off one of the wires for my Orion high/mid amp turn on when the radio turns on, if so which wire? I have read that my rear deck 6x9's are bi-amplified. If this is true, then how can I access signal/ speaker wires to run an LOC for my sub amp so I get a full signal, do I do it from the factory amp, what color are the wires & also how can I access signal/ speaker wires for another LOC for the high/mid amp? Can I do it through the kick panels or must I go behind the dash. Is this possible without the Anti-theft kicking in? Any and all input is greatly appreciated. Thanks:)

Thanks for the replies...Greatly appreciated...Since I posted this thread back in April & did not hear anything except negativity from the dealer when I asked...BTW Chevy dealer told me that using T-taps or splicing will throw off the resistance & may screw up the CPU thus voiding my warranty! Whether or not this is true I decided against it & instead installed a Pioneer AVIC Z1 30 GIG head unit without cutting into any wires using an Axxess GMOS LAN 03 plug n play wiring harness & built a custom box into my spare tire compartment which now houses an 18" subwoofer TC Sounds powered by 2 yellow top Optima batteries an Orion 2250SX "Beast" amplifier and controlled by a Power Bass Accelerator in the dash...THUMP THUMP.