Not the easiest to convert you have to notch the backbone for carb cable clearance. And there's something else I think.  Once together the carb is a royal pain to get at to work on. But for a setup with an airbox probably the best bet, I use one of SBLT's aluminum ones on my 250 and its the best for a filter hands down. uses a 250r honda set up.

I am actually considering doing another hybrid with a 92 chassis just because of the Airbox, but it depends on if I get started building a whole new frame or not. I have to clip it and hybrid mod it so by the time I do all that I may put the time towards a X.