Your PCM can definitely run a 4V, though tuning is likely required.
Electrically, if you install all your electronics from the 2V setup on a 4V, you're really only looking at extending a wire or two (as some sensors are in slightly different places). A 4V typically has provisions for knock sensors that a 2V won't (but I believe that's in the block).
Coil on Plug ignition is the only exception; the 4V coils are wired backwards (polarity is backwards), have a different boot shape, and the wiring runs into the valve cover rather that along the top of the head. You would need to buy a set of 4V coils, separate out the COP wiring from the fuel injector wiring, reverse the wires and extend them to run into the valve cover.