2003 XTR Preview! Shimano’s flagshDrivetrain:

2003 XTR Preview!
Shimano’s flagshDrivetrain:
It is still 9-speed and compatible with current 9-s components, although
there are updates in drivetrain technology.

The new crankset is still hollow, but is now a two-piece setup (the
bottom bracket spindle is one-piece with the driveside crankarm, the left
crankarm clamps onto the splines similar to a BMX design). Bearings are housed outboard of the bb shell to allow for the large-diameter spindle.

Compact drive is the order of the day- a 44 tooth large chainring will come stock on the new crank.

Rear Derailleur:
The rear derailleur is low-regular only- RapidRise.

The new shifters are further integrated with the brake levers, and offer a couple options in shifting technique. It definitely ain’t like it used to be.

Yup, open system, opposed-piston Hydraulic discs, compatible with either post mount or international standard tabs. The rotors are a two-piece, steel/aluminum design that attach to the hubs via a lockring and splined fitting, similar to how the cassette attaches to a freehub body. Meaning, the hub is redesigned as well.
ip group gets an update.