Question about P4 Emitter output in Cygolite Rover II Bike Light

I am not sure if this is in the right forum or not. I was wondering if there was a way to get more lumens out of my Cygolite Rover II Bike Light. It has 2 Seoul Z LED P4 emitters, and runs off of a 2500mAh*4 4.8 volt NiMH battery pack. Cygolite Claims 255 lumens of light output with both lights together. I know that the P4 can produce a lot more light then 127.5 lumens for one emitter. So my question is basically: Is it possible for me to upgrade the battery pack to produce more light? Or does it have more to do with the driver in this cygolite that limits the amount of light that the batteries and emitters can produce?

I am not exactly the right person to tell you but i will make a start on it...

The newest Cree LED grade, the R2 bin, will outpout at least 50% more light than the P4...So you decide if it worths the trouble dissasembling the light etc etc...

BUT
there is one condition to it....Will the driver make up for the increased voltage demand of the R2 (3.6+ volts vesus 3.2 of the P4)
(unless of course you locate some low Voltage speced R2s)..
Probably will but noone can garantee it..There have been instances of early Q5 appliation (using older drivers) that moders got LESS light out of their upgrade...

So time for the experts to jumb in...Kostas

Thanks for the input, I will look into that upgrade. Anyone else have any estimation on whether or not I can increase the output of these two P4 led's in this light?