If you would like me to add something, please comment. As far as custom calibrators, here is a list of what is out there: (Please note, I have not included Livernois because I have no experience with their tune.)
Known widely for their towing tunes. Performance is improved over stock. Most users feel that the way the truck behaves with this tune is the way it should have come from the factory. Known for driveability, not all out performance. They offer an optional powertrain warranty.