New cassette (went from a 34-tooth granny to a 36-tooth!), new jockey pulleys on the long-throw rear derailleur, a new Whipperman chain, and three new chain rings.
The bike also got a new headset, a few new cables, new cross brake levers. One of the aesthetics that I asked them to look at was that my two racks were never quite straight; the rear platforms were never quite level, and it left the bike with a not-quite-square look. They hit a major success on my behalf and I am so happy with it.
One of the issues complicating the rear rack was the conflict between the normal mounting positions and the Travel-Agent for the rear brake. The folks at Thick built me a custom bracket to connect the rack to the brake hanger hole. This is so sweet.
Also, I wanted to move a headlight down onto my front rack's forward bolt-hole, and they fabricated a bracket and used a Paul's Mount to make it work. I am so impressed.
Thick paid attention to a lot of little things. My rear hub was always quite noisy when it free-wheeled, and now it's quiet. All my racks and handlebars present with right angles now; my parallelograms are parallel. It looks very square-rigged and I so appreciate that. It handles real nice and the new drivetrain is fantastic.