Check out my thread and specifically, the Google Sheet. The price is the link.
Check under TUNE/GAUGES. I'm hoping the Innovate boost gauge I got will be all I need for Flex, but might also need the ECA-2 items listed. Phunk included, extra charge, a few AN fittings I think for hooking up the flex sensor. Seb said I need the ECA-2 stuff, don't know why. The gauges included the sensor and will output 0-5v analog needed by the ECU for E%
Mods needed to support 550 WHP Centrifugal SC kit