Steve, did you purchase the ECU from Garage56? Was the installation straightforward?
Yes, from G56, with the fan kit upgrade installed, even though I don't have the fan kit yet. While I wouldn't call the installation easy, it was straightforward. Straightforward because you just unplug it (battery disconnected!) and remove the two mounting screws. It's not easy because getting to the two mounting screw involved working around tightly grouped wiring, and the connector I was finally able to remove from underneath the dash after removing the center under dash trim pad. I would also say a ball end hex key is required for the mounting bolts due to angle constraints. Seems the ECU is the first thing they mount on the chassis before everything goes on! After installation my speedo didn't work, because in my struggle I had dislodged a wire in the connector from the front wheel sensor. Was easy to fix (just push it home) but took a bit of internet searching to find some clues on why speedos stop working, and therefore which wires to examine.
It occurred to me at the time I should build a small sleeve/box to mount that would allow the ECU to just slip out. Didn't want to take the time.
The port for plugging in the computer cable is fairly accessible, but has very small screws you must not lose. During my driving/tuning weekend I left the cable plugged in with a cap over the computer end when not in use. Kept the risk for screw loss to a minimum.