..and now back to your originally scheduled programming......
My $$ isn't in the list of choices. Over twice the highest listed $$ amount.
But..that includes a new tire, CBR lifetime bearings for the front wheel..stuff like that.
My forks were spendy, too. Over $200. I bet on the chance they may have actually been revalved and therefore have a better starting place for tuning. Fact is they WERE revalved..but that kind'a opened up a whole new set of problems.
..that's btw for this thread.
I still have my complete KDX front end, too. I did not use my KDX stem (bought another just to be able to keep the KDX front end a bolt on set-up), so that whole pile-o-parts could be used to offset the KX upgrade cost.
BTW...I see no reference to things like a new tire and new bearings (CBR's aren't your chinese 6004s-for-$6 junkers) in the posts above. Don't forget those parts when you're penciling your budget.
A $450 bolt-on set-up would be great!
re: pointers
If you can get all the parts from the same year KX it will be simpler than wondering or documenting the what-fits-what questions.
A forks AND clamp assembly from the same year makes it eaiser.
A forks and clamp AND wheel assembly is even better!
FRP sold me a KDX stem for about $50. That saved me messing with an in-the-clamp KX stem (my clamps didn't come with a stem anyway) and the aforementioned messing with the KDX clamp/stem, too.
Good luck.
You will
love 'em!!!
...if you don't...there is either something wrong with them....or something wrong with
you! 
. I just saw that the forks I was going for went way above my snipe price. Maybe I should just get me a KX250 or 500. They have USD forks on sure enuff. 
I'll miss my comfy seat though. 
