It will be easier if you spot any 2008-2011 Impreza overnight, and see for yourself. Brightness perception is subjective and variable enough when evaluated in person, and photos can show anything depending on exposure time.
OEM halogens aren't horrendous, they aren't exceptional either. Fortunately, a very effective, easy, cheap and glareless upgrade does exist with a H9/H11 bulb swap in lows, and HIRs in highs. IIRC, you're adding over a thousand lumens per headlight with everything turned on - while maintaining the proper cutoff line and light distribution.
Now, if that's not enough, a bixenon retrofit (changing the projector assembly within the headlight, adding D2S capsules and ballasts) will still cost you less than new OEM HIDs from Subaru.