LS wiring harness guidence needed

[bloibl]

Guy's my Brother and I are working on a C-10 truck and we are putting in a LQ4 motor and 4l80 transmission in the truck. We have all components including the computer, throttle module and all wiring out of a early 2007 2500HD. We are at the stage that we need to address the wiring and computers. what is the best way to go regarding the wiring harness and computer for my ls motor. Should we buy all new or send off the existing wiring and computer and have it re flashed. We are not sure if the aftermarket world has put out cost effective products or is it still more effective to send this stuff off.

Also we are putting on a ls2 intake if that matters. thanks in advance for the help