I just got a copy of the dealer blurb on the 2003s. I only got a chance to scan the doco quickly but from memory (it's sketchy - I'll correct any errors once I get home and check the document, I promise) these are the highlights.:
1) No mention at all of the 380 two-strokes - looks like they are history!
2) New model: 200SX, 200 motor is reworked for more power
3) New, lighter motor for 250SX with shorter cylinder assy and conrod, more upright engine and shorter chassis
4) New lighter crank for some 2-strokes including 250SX and 200 E/XC, SX - for "less vibration, better response"
5) General issue: WP 48mm forks, revalved shocks
6) 450SX "designed for same performance as 2002 520SX" according to KTM
7) 525SX with 41mm carb, larger ports
8) "Improved" 250 RFS (I haven't even seen the unimproved one yet).