I replaced my low beams with Sylvania Halogen bulbs (part # H5006). They are a great, bright, and cheap relacement available at Advance Auto. The problem is that my stock pigtails fit on the new bulbs VERY loosely. The connector would fall off on very minor bumps.

Solution: Trim about 1/8" all the way around the tulip-shaped pigtail's perimeter. This will allow the lugs of the bulb to reach firther into the socket and seat firmly.