This.
WAMS (Chris White) has been a long-time member of this and many other forums. He has very in-depth knowledge of GM BCMs, HMIs, factory programming, and all the electronics. His follow-on support is also great (you won't get ANY from the ebay sellers).
I would spend the extra money and go with WAMS. You will get a factory system from a higher-model truck that is guaranteed to be plug-and-play with your truck, with great support too. Easy-peasey ....