ED-E My Love: Speaking with Lorenzo with ED-E in your party will unlock an unknown audio log.
If you choose to assist Head Paladin Hardin to overthrow McNamara, you will not be able to complete the air filtration system quest, if you've spoken to Lorenzo about the filtration system before Hardin takes over you can still turn in the parts to him, but McNamara will no longer have the completion dialog. If you do not speak to Lorenzo about the filtration system before Hardin takes over, you can still get the starter dialog from Lorenzo, but you will not get his dialog for turning in the parts even if you have all the parts in your possession.
If you have chosen to turn in ED-E to Lorenzo while tasked to find replacement parts for the bunker's air filtration system, Lorenzo will disappear from the game until ED-E is sent back to Primm. PC users can fix this problem by using the console.