Just wanted to chime in that I have been experimenting with the $5 version of torque in the prius, it is completely awesome, and crazy cheap if you have a bluetooth android (gps would be a plus also):
Equipment (2004 prius)
2nd hand Sidkekick 4g
$12 OBD adapter
Newest V1 5 ELM327 Torque Android Win7 OBD2 OBDII Bluetooth Diagnostic Scanner | eBay
$5 torque from the play store
Install the free pids for your car, i.e.
Gen2 Prius: Custom PIDs for Torque (Android App) with formulas | PriusChat
So trying to understand what the prius is doing is a lot easier now, I might even be able to have a soft button on my android for a kill switch 8-o
Currently I have 6 gauges on the main screen,
1. mpg graph
2. ICE load (mostly a "the engine is running" indicator, and I try to keep it in the 60-70 range when it is running)
3. HV battery hp (goes negative when charging)
4. brake friction pad hp (so I can tell when I have exceeded regen and am just making heat).
5. MG1 hp
6. MG2 hp
It is pretty awesome and so affordable and so easy. I don't know how accurate it all is, but I'm geeked to have some good insight into where the power is going.