PVore-3 is very similar to PVore-2.  Besides the notable difference in solar cell size, the chassis is a bit wider and longer to make use of the extra room under the solar cell.  As for performance, Pvore-3 is about the same as PVore-2 if not a little slower (I believe the increased length is responsible for this).  The increased solar cell size increases the voltage output, allowing PVore-3 to operate in lower light levels than either PVore-1 or PVore-2.
     The two extra 47k resistors on the potentiometer you see in the top-right picture were an attempt to make up for substituting a 20k potentiometer (blue piece between the IR Diodes) in place of a 100k.  With the 20k trim-pot, I could not get the circuit and had to finally replace it with a 100k (grey piece).  Next time I'll stick to the schematic.