Pioneer finally released the long overdue firmware update 3.18 which brings ALL features of the DJM2000 Nexus to the old DJM 2000.

Here is the changelog:

Ver.2.01 -> Ver.3.18 (20 December, 2012 Update)
- Added BEAT SLICE REMIX.
- Added SYNC MASTER.
- Added PEAK LIMITER.
- Changed OSCILLATOR1-4 of SIDECHAIN REMIX to NOISE, HI-HAT, CLAP and SNARE.
- Improved SIDECHAIN REMIX usability in SAMPLER, PITCH and GATE.
- Added manual effects to SIDECHAIN REMIX.
- Manual effects mean that when touching the pad, effects are triggered in this version,
 whereas increased volume level triggered the effects in the previous version.
Source: http://pioneerdj.com/support/product...DJM-2000&t=110