The PowerCommander PCIII-USB should already have the Rev-Xtend feature if it was made after a certain date, see info from PC web site below:
I just got a new PCIII USB, but it pre-dates the upgrade. I see that for $40 you can buy a kit to do as many as you wish:
"You also have the option of purchasing a firmware programmer and the necessary software which will allow you to update an unlimited number of units. This package is part #HDREV and can be purchased for $40.00."
So if there are a few of us on here who'd like to do the upgrade, maybe we can club together, buy the kit, use it, and send it on to the next guy... Anybody else interested?
Jim