Also, the screw-based adjustment for the second extruder relative height works quite well, and takes a lot of the fiddliness out of dual extrusion. The extruder mounts also fit together much more snugly now, which helps when swapping extruders. I have to admit I did not bother with the replacement parts for the bed mount, as I haven't had any issues with belt rubbing.
I did note that the set screws fastening the extruder gears to the motor shafts became loose surprisingly quickly; I retightened using Lock-Tite and am now good to go.
The one thing I haven't liked so much is the new z axis end stop adjustment device. I prefer the one by GGY in the Hacks forum, which does basically the same thing.
Overall, though, very pleased with the results. I believe the upgrade has significantly improved my printing reliability.