This is basically a complete bike but I plan on keeping the front end as a spare for my IT
The DT200R has got possibly the worst front brake in the universe (ie single-piston front caliper).
TT250/350 forks are the same diameter (41mm) and use a much better twin-piston caliper.
For DT200Rs, fitting TT forks and front brake caliper is a common upgrade.
The disc and master cylinder are the same between DT and TT.