Variable cam timing

Hello! So I recently swapped my engine to a ej20x which has variable Cam timing however the 2005 forester I swapped it onto did not have this originally, I believe they call it AVCS and at the moment I dont even haved them plugged in. My question is would I need an ecu with this system already so I can properly tune it?

Thanks, A

You really would as the ECU not only needs wired to control the AVCS but also, if you're using the OE ECU, it needs to have the strategies in the firmware

For what it's worth, people often run the EJ20x with intake cam phasing only, leaving the exhaust system unplugged. It's not ideal, but it can work fine in an off road use situation.