Hi,
if its just alittle darker, i wouldnt bother unless your good with electronics. (theres a knob to brighten the lights on the left of the wheel)
my dash is brighter during the day(or when the car is well lit inside), but when it gets dark, the gauges also dim. i assume this is so that it doesnt strain my eyes in the dark. (i've noticed this when i enter tunnels)