They claim this retrofit is a two hour job - probably for someone who
has done one, not for a first timer. That's not to say the job is
difficult or physically hard. it's not, but the items to be worked on
are unfamiliar.

The kit that was sent to me was a return, complete with greasy finger
prints on its instructions. That's due to Performance Products, not
Unwired Tools. Its heater hoses didn't fit so I had to substitute,
Unwired wasn't aware of that until I mentioned it to them; hopefully
that's now corrected.

I suggest you think about the location(s) of the electric vacuum valves
and the controller; then block out an afternoon for this retrofit - and
have access to another car in case you need to buy a substitute part.

The job has these phases:

   Remove the glove box to access the amplifier. Remove the amplifier
and add some jumper wires to that harness. Reinstall glove box.

   Remove the servo ( I also removed the weeping aux. water pump.)
Install the hot water valve in the heater's "hot" line and a piece of
pipe in the heater's return line. (The instructions tell one to do this
heavier work AFTER the vacuum lines etc. which is, IMHO, backward as one
then disturbs the vacuum lines etc. while working on this heavier plumbing.

   Then one installs the electric vacuum valves at a logical location
on the fender or fire wall (be sure to run a ground wire from this
bracket to the car's body). There are four valves, one for the hot water
valve, one for the fresh/recirculating air, one for the upper vents and
one for floor vents. The directions as to what connects to what are
clear; YOUR decision is whether to retain and plug into the old servo
vacuum harness or cut the old vacuum lines (one by one to avoid
confusion). This decision and your location of the paperback book size
control box, ties into how you want the end result to look - neatly tied
up or a kludge of tubes and wires etc. . Neat takes time.

    The electrical wiring is relatively easy (but don't tug on the
wires as some may pull out of their connectors).

Finally, the control box is plugged in. Drive the car and then, at
operating temp., calibrate the controller (one tiny adjustment screw).

There's no change to the original console / dashboard appearance, all
the changes are under the hood. I especially like this feature.

The kit omits the OEM cold engine lock out feature. I restored it by
salvaging that vacuum / temperature switch from the very bottom of the
servo and attaching it to a flat brass plate that I soldered onto the
copper pipe in the heater's return line. The vacuum switch is cut into
the green / white (fresh-recirc) vacuum line. It works just like OEM,
even without the electric aux water pump.

The kit includes a five year warranty.

I like my old car but hated that lousy servo - this kit solves my conflict!

Hope this answers your question.