I've used the KP Technologies device before, put it in my SRT-4 for the reverse tilt down. It works pretty good. As has been pointed out the key to the tilt down is a "memory" mirror system that has position sensors which don't exist in a less luxurious car like a Subaru.
The KP timer thing does the trick, even if you think you adjust it perfect (it has separate up and down timer settings) it is not quite it will drift a bit over time, the unit has a feature where it will only activate when you shift to reverse twice in a few seconds, so you only use the feature when you need it, that way there is less drifting of the mirror position over time.
No reason to worry about a "universal" application, every mirror adjustment in every car works the same way...one common "ground" and one wire each for up/down side/side direction motors, the KP unit just taps into the up/down and ground wires from the switch.