I have a 2004 V6,and the electric windows have been a headache..The guide plates which are siliconed to the glass pop off.Its a common problem on the mustangs..I just recently replaced my headlights for the second time..I bought the smoke headlights from american muscle.Unfortunely they block out the light too much..I went to LEDS and now they are brighter..I had the same problem gettingt the bulbs i as you did.I had to leave out the round sleeve that pushes up against the back of the headlight fixture.I used the old retainer off an older fixture..Im worried about it leaking now.On the drivers side i was able to get the sleeve on.