The implant itself takes concentration. "In all cases, their use requires concentration and a Half Action." I'm not 100% if that actually should be a half action each turn, but it should be distracting (I'd limit them to half actions in combat if they intend to use it).
It otherwise functions as an auspex when actually in use.
Good quality allows re-rolls on all perception based tests "when using its functions" (I read that as meaning when I do anything perception related and have the device active).
Note this means rerolls on scrutiny, which is also quite helpful. Theoretically on psynisciance as well, but thats debatable.
As far as the auspex functionality goes:
Just by using it in a barebones fashion, the user has +20 awareness. Therefore, those with the implant, when using the half action to activate it it, also have a +20 to awareness (I might be open to removing the notion of having to constantly use a half action. Honestly I see no issue with the loss of an action type, they took the time to get the thing implanted).
The Tech Use test is a highly specific feature, and is indeed the "motion tracker" effect you mention. By making that test, the user can suddenly percieve things out of their normal range of perception (through surfaces, etc.).
Good quality increases the awareness bonus.
The device has a 50m range.
The thing to know is an auspex has two distinct uses:
1. +20 to Awareness tests
2. Make a Tech Use test to get a detailed "reading" of the area
Someone untrained in Tech Use can still use the device.
It sounds like you're confusing those two as the same thing. Using an auspex to get the +20 bonus doesn't necessarily give you the "motion tracker" view of things.