I have the less expensive one from Amazon.
It works perfectly on my 2018 LT.
My truck stays on V8 all the time.
The only issue you might have is if you use the GM/Chevy app to monitor vehicle diagnostics. You won't be able to get vehicle health info on the app if there's anything plugged into the OBDii port.
Also, my mileage did drop. I get an average of 14.5mpg around town, about 1.5mpg less than with DFM enabled.