i ordered these shocks early november, but i have yet to receive 'em. i talked to the guys @ calandra and they said the reason they were held up was due to the instructions. apparently, they wanted to make the guide "dummy-proof". they said that a seasoned hobbyist shouldn't have a problem assembling 'em, it was more for the newbies. the clicker portion of it is pretty delicate and if you try to assemble it by clamping down the shaft and the clicker, it will be damaged. anyway, that was sort of how it was explained to me.
as for how does it work? unlike conventional shocks, these shocks use a very light weight oil. 20 wt. @ the softest setting (there are 4 settings) is equal to 40wt and the stiffest setting is equal to 80 wt. it doesn't work like the associated vcs system. i know trinity makes shock oil as low as 15 wt. (maybe even lower). just take this into consideration and you should be fine.
as for action, i doubt they'll be as smooth as tamiya's shocks, but i think the adjustability will more than make up for it. the calandra guys also told me the oval racers are using 'em w/ great success.
the shock bodies are designed to fit the associated springs. yokomo will work as well.
i'm going to try these out on my tc3, and if they are as good as i hope they are, i'll get a set for my gt-4.