The EV mod is, in essense, not much more than a momentary switch between two wires. The Prius computer already knows about EV because the international models (if that term can be applied to a foreign car
) of the Prius come with an EV switch, while the US model does not. The Mod just turns the existing mode on/off.
As for harm to the battery, I would expect it will depend on how you use it. You probably already know it's a bad idea to let the battery to go completely dead. Treat EV the same way. If used with a modicum of common sense, I would expect you will not see any noticible difference.
As for harm to the battery, I would expect it will depend on how you use it. You probably already know it's a bad idea to let the battery to go completely dead. Treat EV the same way. If used with a modicum of common sense, I would expect you will not see any noticible difference.