Not the first derailleur I've ever fitted, but the first on a carbon bike and the first replacement hanger. Had to do a bit of dremelling on the latter to get it to fit snugly - couldn't get a pukka Trek one.

Surprise, surprise: my p.o.s. torque wrench doesn't have a small enough bit so I had to do it by ear. Nothing broke.

Test ride was fine. Ouf.