1) Yes and no... it will likely work for you fine when the car is on or off, but will likely drop out while cranking the engine. If this is a problem, do a search on "tank circuit" and read.Originally Posted by entr0py
2) Yes, the voltage regulation is within the limits of the 60W DC-DC board that comes with the C134. If it turns out to be too low/high, the page did say that it has an internal potentiometer for a bit of adjustment. It should also provide enough current.
However, as much as this thing costs ($120 +$50) you might as well buy an Opus. The Opus will likely not fit in the C134, but it has a builtin shutdown controller and is quite proven by the users here. (I do not own one, so I cannot vouch for this myself, but having many satisfied users and no dissatisfied users cannot be too bad)