Over a lengthy 3 years, my KDX has been completely rebuilt-top to bottom/side to side/front to back. Whew. way more in my bike than it will ever be worth BUT I know what I have. I will get some pictures up.
Regarding my forks, I had a well known southern guy rebuild and gold valve them,installing a set of race-tech .46 springs. i weigh 170ish in shorts so that translates into around 185ish suited up/and with water pack and etc. this set up beat me to death and gave me arm pump that wore me out after 25 miles of single track/woods riding.
A great friend of mine that knows KDX's well told me that particular setup would be too stiff for me( he was correct) but the springs were all that I could get my hands on at the time.race-tech doesn't carry older bike items it seems and my very helpful and knowledgeable kawasaki dealer could not locate anything softer spring wise. Above mentioned friend suggested that we go with the stock KLX springs which should be .38, too soft for my riding weight yet softer than the .46. So we changed springs out and my old bike tracks and soaks junk up and has me smiling like never before !

I used the KLX front brake and tucked the brake line in really well at caliper.It works very well. Front/rear brake systems were rebuilt so stopping isn't an issue.New front brake setup actually seems to work better than original KDX system but keep in mind it has been 3 years since I rode it.I have 14 hours on the whole bike as of this post.
My rear shock was revalved but not gold valved so it works well and keeps me planted. I've owned this KDX for 12 years maybe. MANY,MANY hours and miles on it (above mentioned friend knows) and my bike seems to be dialed in as never before. Still soft up front but wow,it soaks it up man.
Quick mod list-
boysen rad valve,Pro Circuit pipe/304 silencer(sometimes FMF 2), no toil filter/air box mod, probably every piece of armor made for KDXs excluding front/rear brake guards,cleaned up new cylinder at the ports,and all the woods oriented pipe guards,hand guards,full skid plate,etc.
IMHO I feel the KLX front end was a worthwhile endeavor. Simple swap, everything matched up,and what little turning radius I lost I regained by shaving a little off of my Devol radiator guards at the point that attached to the frame. NO compromising of the integrity of the guard so I am okay with it.
I appreciate all the info learned as I lurked over the years.I will attempt to get some pictures up with my new plastics and etc. as soon as i figure out the way to do so. I wound up with 2 sets of Race-tech .46 form springs(for KLX300) so I have a new in the box set to trade for a set of .40 or .42 or maybe a .44 if anyone is interested.