well i have tried
the ebay unit and it works to the point that i can go 2wd however to re engage 4wd you need to shut down and restart the system,
the hks unit works very similar to the ebay unit
what i want to do is run 2wd for 95% of the time
its only to launch that i want 4wd
whole idea is to save the front diff, axles, transfer
thats why i was thinking of a manual hydraulic system