Have replaced both low beams on mine. One was so dim it barely projected light, even with a new bulb installed. It turned out that water had gotten in thru the rubber boot on the backside and the reflector had totally corroded.
HELLA 009071081 Micro DE Premium Series 12V Single Halogen Low Beam
Paid around $90 each. Worked much better on low beams. However then I converted them from Xenon to HID. It was easy to convert the Hella micro's. You change the bulb from 55w H3 halogen bulb to a H3 HID Xenon bulb and install a ballast for each light. Only real difficulty was disabling the daylight running light. The reduced voltage while in daylight running mode will drastically reduce the ballast light. I am now very happy with my low beams
Some lighting experts will tell you that the Hella Micros halogen reflector and cut-off curtain are not suitable, but it works well for me. I do not get excessive bounce-off off the paving that can reduce your night vision.
Good Luck!