Correct me if I'm wrong, but......
Kayaba makes most of Yamaha's shocks, including the dirtbikes and ATV's.
Showa makes most (if not all) of Honda's shocks.
These 2 companies probably have more field time with testing on works type bikes, custom one off's, and an endless budget than any 2 shock maker's combined.
If you think about it....Kayaba makes all of Team Yamaha's custom shocks for their racers in the Supercross series, and the MX series. Plus all of Yamaha's trikes and quads back to date. (from what I know)
Showa makes all of team Hondas shocks (like Ricky Carmichael's 25,000.00 dollar rear Supercross shock) plus they've probably had more works quads (the honda Rincon that won the 2002 Baja 1000.....) and trikes (they used to be HUGE into trike racing) than anyone.
I would rather have a custom set of shocks from these guys than any aftermarket company out there, to bad no one could afford a custom set.
Just my thoughts.....