Enginer BMS have changed drastically from the time that Daox installed his kit.
Now they have a remote head unit and data logging capability.
Also, there are plenty of 3rd party BMS's.
For $405 you can get one from Pacific EV that, like the Enginer system, does data logging.
Electric Vehicle Parts --- PHEV BMS -- Simple BMS for bicycles and Enginer Plug-In Prius Kits
Don't skimp here, choose the logging version rather than the non-logging version.
It is a great alternative if you choose not to use Enginer BMS.
You can get it directly from Pacific EV and have your installer hook it up for you.