The 125X and 250Z were indeed seminal bikes. Both models stood on the shoulders of the giants of the RM series that had gone before. In Suzuki's typically conservative style they used ideas that had been first developed elsewhere (watercooling and mono/linkage rears), but put it into a package that was so trick it simultaneously reduced the 'hop-up' accessory market to suppliers of nothing more relevant than 'single-sided airfilters' and established the fundamental layout of the (two-stroke) mxer as it is raced to this day. Except for one exception, of course, USD forks. Karmic justice in a way then that the aftermarket guys forced the final evolution on a grudging Suzuki in the form of the Simons UDX60s before the end of the 250Zs model year. For me though, there's a little more irony, in that as class structures stand, these bikes are unlikely to be 'remembered' by race-grids in the modern age. As long as those structures penalise ground-breaking bikes by effectively making them the oldest bikes (and therefore 'least developed' bikes) in their age bracket, so we'll probably see less of them raced than their technical achievements really deserve. I know its not necessarily that simple, because some of the looming 'seas of red' of 82/83/84/85 CR Hondas are potentially at risk from magnesium case-cancer. Whatever happens competition-wise, if you've got a nice low-hour unrestored 125x or 250Z I'd be hanging on to it.......and the RM370b of course.
