No change at all that will affect speed and performance. Haven't you studied physics? Don't you understand that the force by which the locomotive pulls is what the speed depends on? Absolutely no difference at all, HWH/SDAH/BCT Rajdhani are running with 2005 made coaches. Bhopal Shatabdi used to run at 150 km/h with 99-2001 made coaches.
Just because its AP doesnt mean you need dumb reasons to establish the fact that it can still do better.