The idea that removing a Sea-Doo 325's speed limiter requires permanent extra hardware is common, but it is based on how older SCOM devices work rather than how the process has to work.
What Changes and What Doesn't
Once the setting is changed, it stays changed. There is no ongoing process running in the background that needs a device present to keep functioning.
The Plug-In-Once Process
The M-JET Speed Limit Remover is connected once, the change is applied through the app, and the boat keeps that setting long after the device has been unplugged.