Ordered in January 2016, Installed Last weekend
it was 860$
what was included:
-MS2E ecu
-Db-37 harness
(programmable output, obd interface and digital wideband com cable)
-instructions!

First things first. physically mounting the ECU in the car.
Rev's ECU had no mounting tabs or any hardware that allowed me to get it into the OEM ECU location.
A guy that had the same ECU on miataturbo.net made these mounts out of aluminum.
I went and made some from thin steel stock and drilled holes. it took a lot of test fitting. but it works fantasticly. the mounts have 2 small holes that use the ECU Case's screws to hold it up. beware, you will probably dislocate your shoulder a few times trying to get the ECU up under the dash.
this picture is not of my mounts specifically, but i cut them out exactly like these. I had managed to get the ECU mounted under the dash. and there is no way im taking it back out to get a picture.

Installing the ECU.
the OEM ecu wire harness plugs right in to the new MS ECU.
you also should plug in Rev's db37 harness, your DB-9 tuning cable and the vacuum line before finally mounting it.
an GM IAT sensor is a must.
I took my BEGI throttle pipe to a fab shop and had them weld in a 3/8"-npt pipe bung
as seen on the top left of my begi pipe. the GM IAT sensor and connector can be found at most local auto parts stores, or on ebay.

for mazdaspeeds you need to clip the 2 wires going to the OEM temperature sensor (other side of the begi pipe) and splice them to the wires of the new GM IAT.
run a vacuum line from the back of the intake manifold to the nipple on the back of the new ECU.
mine is teed from the boost gauge sensor.
download Rev's supplied INI. file, save to desktop
Open Tunerstudio, make new project
(tuning cable is plugged into laptop now and ignition is on)
new project, choose rev's INI file (thats the firmware) and make the project. test the comm port (tuning cable) and you finish the setup (per instructions) and you can acsess your ECU on your laptop.