personally, i think all he should do is adjust the shutter shorter
i dont know what iso he used or f-stop.... but at 2.5sec, i would drop it to say 1 second and increase the fstop a little, no more than 2or3 stops. darken up the blacks, ease in some detail in the middle of the fireball (if there is any to reclaim) i dont think the change from 2.5/1 sec will do anything for exposure, but i do think it will help eliminate any noise there might be. i just feel it should overall be darker with less hotspot. but im viewing on a calibrated lcd...
just wondering.. i hear lots about calibrated LCD's... why not spend that money and get a good tube Monitor? As far as I know they are vastly superior for color and contrast reproduction.