I got mine from Fuelmoto. I think it was $254 and the install is very easy and straight forward. It plugs into the accessory port on the power commander. I doubt I will use it in action but more for on bike tuning which it does very well.
You can download maps to the PC III, there is limited tuning(ie; the low, mid, hi tuing options you have on the PC III), you can log data(record engine FI map parameters) that you can convert to excel spread sheets, various other small functions oh and a tach.