I went from a PCIIIUSB to a PCV (because I had to - upgraded my 16bit ECU to 32bit). I believe there are more options available for the PCV like a second map you can switch to with an external button and the fuel map is more granular but if your bike is already dyno'd on the PCIII and it's running well, I think swiching to a PCV is a waist of $$ IMO. By the way, you can convert your PCIII map and load it into a PCV if you decide to go that route anyway.