Forks

FZR250 3LN model forks are a straight fit for the SR, maybe OK for XT. From memory, the length of the forks is about 780mm. The XT frame is different geometry and you may want slightly different length.

That's the easiest major component change I have made. All you need to do is get some spacers made to fit inside the standard wheel bearings to accommodate the FZR250 spindle diameter of 15mm and some wheel spacers to align the wheel. If you are using a drum front brake you won't even have to make an adapter for the brake caliper.

I am racing the SR and the forks are much stronger being 38mm and don't need a fork brace, so no binding problems either.