thank you for your order sir!
With the XDI-EVO and adapter line that you ordered from us, I would recommend this kit:
Bluetooth flex fuel analyzer with ethanol sensor support for real-time fuel data. Includes analog and frequency outputs for accurate ethanol content readings.
fuel-it.com
You can either get it with a hardwire line for a physical gauge, or use the Bluetooth adapter for your phone. For our cars I would recommend the GM 13577429 sensor, you can either buy it with that kit, or online. I've found that RockAuto/eBay/Amazon have the best prices, just make sure you don't accidentally buy the 3D printed mount and purchase the actual sensor.
Other than that, you have everything you need on order, and as soon as it ships we'll toss you tracking information and you can let me know if you have any other questions regarding install. It's pretty straight forward.