Old post but I tried this, I currently own a T880 and a T992. I have been playing the Bronze neck on the T880 for about a week now, just a little bit every day. Trying to sum up my thoughts about the three combinations.
T880 - Using stock neck it plays great, it has a little bit too modern and too bright Japanese sound for what I want. This is not a complaint, the T880 is one of the better horns I have owned or played, it's just not quite "perfect" for me. I feel like I want this horn but with a slightly more "neutral" sound.
T992 - Key system, intonation, and ease of play are all slightly better than the T880. The sound is difficult to describe. To me bronze makes the upper pitch / harmonics of nearly all notes softer. It rolls them off a bit, it's like taking the treble knob on your stereo and turning it down some. The mid and the bass seem mostly the same.
T882 (what I named the T880 with the T992 Neck) - First off, it plays easier and it really feels like it has better intonation. I didn't expect this, my expectation was it would play the same. The tone has a smaller change to it similar to the T992, the high end seems softer. It takes away nearly all of that modern brightness that I don't like about the T880 and makes it more subtle, more rounded in a better way. Somehow the neck adds some other flavor or change that I can't figure out, but I don't like it. I am not sure what I don't like. I just can't decide if I like the T880 better with the original neck or the bronze one. Maybe some more playing will help, I am also going to change mouthpieces and reeds a little to see as well.