I might be able to help. My girlfriend has been racing 03 and 04 KX250s in enduros for a while now. She's a B level enduro rider and competes in the B250 class. She ended up second last year against the guys. Out of the 03 and 04 250s, the 04 is much better off of the bottom. It has a smoother transition into the midrange and maybe a bit more over rev. We havent ported it and feel it doesnt need it. She has a 11oz fww, a Pro Circuit 296 silencer, this smoothed it out and seemed to add a touch more on the bottom. She also has a V Force reed cage. The stock pipe seems to work best for her In comparison, her 03 has similar mods but realy lacks bottom end. Its not so noticeable in the more open terrain but very noticeable in the rocky, hilly enduros that we race in PA and NY. It has to be ridden pretty aggresively there. We both run 13/51 gearing, I race a 04 also, 13/52 on the 03. Our terrain ranges from extremely tight southern NJ woods to very hilly, rocky PA and NY woods. You can also pre load the power valve governor spring with washers, this pretty much takes away any big hit that it may have. Also, depending on your wifes height, you may want to lower her suspension properly. Not the lowering link, slide the forks up way, but by sending it off to a reputable co. and have them revalve and lower the suspenders. My girlfriend did it and will not go back to the stock height suspension. Hers was lowered 1" and it made a huge differance. She is much more confident riding it. I almost forgot, in 05, Kawasaki changed the engine completely and they are supposed to have a more violent power delivery, she bought a new 07 last year but hasnt ridden it yet. It still has the protective plastic all over it. She will probably start tinkering with it at the end of this season.
