Do I need a Haltech for the Haltech WB?
 

I no longer have my Haltech but I still have a like new Haltech dual wideband sensor and module thing. If I had a wideband gauge, would it still display without using a Haltech ECU?

No need for the ECU. Haltech also now has display gauges available with the correct calibration to work with the controller.

Awesome, thanks a lot, now I don't have to sell