I had a 1984 RM250 E as my first VMX bike.
I brought from a Viper fast guy who had blueprinted it, stuck the Z head on it, bigger carb, etc...
It handled really well, motor was a midrange and top end screamer (a bit like Suzuki59, I have heard..), Full Floater was good. The 84 Hondas I came up against seemed to have more low end but the old Pro-link issues....
I now have a 1983 Honda CR250 and it shxts all over my old 84 RM. Broad power-band, low centre of gravity, turns like a dream, & now with an Ohlins on it, hopefully good suspension. Just needs a decent rider and it would be a great!