On the bottom of page 15 of the instruction manual:

"NOTE: It is recommended to mount the ECU in a location away from excessive heat, vibration, possible water exposure and as far away from spark plug wires, and Ignition related components as possible."

Yes. I 100% know that there is not a distance number like "must keep ECU exactly 12.67845 inches away from ignition coil".
This post is WHY you keep the ECU away from ignition parts.

The ECU uses Bluetooth to communicate with your tablet/phone.
So the ECU case is not Shielded.
The same none shielded case that lets Bluetooth radio waves in, and out for communication purposes.
Can also let ignition radiation into the case, and cause undesirable operation of the system.

Hence why you keep the ECU away from ignition components.

Remember as the ignition components age. They have a tendency to produce stronger, and worse radiation that will effect the operation of the system.

So please keep the ECU as far away from ignition components as possible.

Thank you for reading this post.