Just putting this here, I think it's the best place.
Most car rentals pick up and return is now in terminal 1. It's a bit of a shlep and slow.
Also, I just returned a car to sixt, and was logged back in 75 minutes after they printed the contract, they charged for a full additional day. Said the system won't let him waive it but he'll send to his manager. Not holding my breath.