The Fcon V-Pro is the one you want... the only reason I am selling mine is because of a lack of harness for the PNM35 (HKS tell me that the Z33 harness will not be suitable ).
It is a standalone ECU, but in the VQ25det it is in piggyback "format". Basically instead of adding/subtracting x values on top of what the OEM ECU does, it sends it's own values based on your tune... totally ignoring the variations that the OEM ECU sends to the engine.
It, unlike the eManage, removed the speed limiter and can (as I have stated before) change how the throttle reacts.
Only thing it can't do is manipulate the cams, but as Scotty may attest, neither can the eManage/Vmanage combo unfortunately.