Kyosho's slogan for this thing is "Beyond the Extreme", and it's exactly that.
Here's how I got it, with a Dodge Stratus body and a Team Atlas 23 Turn motor:
The front end has loads of carbon, alloy shocks, foam bumper, a swing bar, full turnbuckles, ball bearings, and a front one-way unit. The front one-way is not shot, which is great, as the KX-One's front one-way is notoriously fragile and might break in less than a single run. Note that the steering links don't use the traditional touring car system but are directly connected to the servo:
A look at the bottom of the car, with the single belt design having the belt run level with the bottom of the chassis:
Removing both bathtubs gives the car even more of a classic Optima look:
:
).
instead that made taking apart the universals a major pain in the behind, and that also had ran into some of the bearings, fusing them to the CVDs in a sticky mess 
. I had to resort to soaking the CVDs in WD-40 overnight to get them apart. I was extremely happy I had some spares to replace the collars that prevent the CVDs from disassembling themselves while running, as they ended up all scratched up from the pliers I used to wrench them off.
or some inventive propping up of the already assembled part of the chassis (as I did, lacking two additional hands). Now access to the transmission on this car is about as bad as on the Optima MID; the whole car needs disassembly to reach the transmission. The rear delrin diff outdrives are stock, by the way:
