The best situation would be to have a flat LED array with all the LED's facing the lens. With that bulb LED you would need a really good focusing mechanism to capture and focus all the light. It would be best to mount the LED flat array as far away from the lens as you can get it to have more even lighting. Also getting rid of the socket will help with reliability. Many times, corrosion is the cause problems with tail lights. You can direct wire those LED arrays so there are not contacts or sockets to corrode.