We have 2005 T2000 that came with an ultegra FD 6503 front derailleur on a 30/42/53 triple. Rear is 11-34 9 speed. Ultegra brifters. It shifted well for years. I also installed a n-gear jump stop which helped shift down to the inner ring more quickly by allowing the low limit screw to be backed off.

When we wore out the 42T recently I replaced it with a Shimano FC 5603 39T chain ring, thinking there could be an advantage to sticking with Shimano ramps and pins, and being unable to find the 42T middle ring anymore. I could get the FD 6503 to still shift okay, but it was definitely more finicky than before, and one out of every 4-5 shifts to the big ring was grindingly slow.

From this forum I learned that there is a wide range of front derailleur cage designs, and I happened to find a lightly used dura ace FD 7703 triple on eBay for $35. This derailleur was designed specifically for 30/39/53 triples and the inner cage is much deeper than the FD 6503. Wow, what great shifting. Every shift is immediate even under load (I do not announce shifts to the stoker) Trimming when using the middle ring is a bit touchier, but I can't complain about that as it is operating the way it was designed. I'm sure it would still work great if I swapped out the inner ring for a 28, which I will probably do if we ever wear out the 30.

Not trying to talk you out of a DI upgrade, but based on my experience it is possible to get a 9sp ultegra triple to shift really well with the right hardware and adjustment. On this last point, I found Sheldon Brown's article on FD adjustment very useful.