I don't think putting the black part from the aftermarket headlights into the OEM back will work. The Aftermarket headlight has completely different reflectors for the low beam area, and it just wont work with the OEM one. You can tell that the light is being limited by the black part, you're getting two light spots instead of a distribution of light. The actual reason is because the semi-spherical reflecting backing for the OEM low beam doesn't marry up with the opening introduced by the black part. But I could be wrong - in my opinion just use the aftermarket headlight, I did and have been for years and no problems at all.