Sax is a very difficult instrument to emulate and capture on a keyboard DJ. Using and mastering the pitch and mod wheels helps, but your always going to be at a disadvantage trying to emulate a sax with keys. The samples themselves may sound brilliant, ( and the ones on the 2000 are rather good ) but without some midi controller work and filters, it's tough to do. A trained ear will always be able to tell the difference between a midi sax and a real one.

Physical modeling and the use of a breathe controller, done right, can get you very close DJ. I saw a kb player use it during an Eric Clapton concert , and, at least in a live setup, it sounded like the real thing.

AJ