My knowledge of electronic circuitry is close to zero and this installation is only an example of how I performed mine. Your Piston Honda may be different (my display, for example is red) and should check with Harvestman before performing the installation. Responsibility and all the other stuff is not mine if you wreck your modules. With that out of the way, the installation was simple. You'll need a 3/32" hex screwdriver to complete the installation and you'll need some balls to rip apart your Piston Honda knowing that you could potentially damage it.
1. On my Piston Honda, the top board wasn't screwed down onto the spacers of the bottom board so I was able to pull it off the pins without any hardware.
2. With the supplied hardware, I used the screws and tightened the threaded spacers onto them to create a bed for the expansion board to rest on.
3. The expansion board slides onto the pins horizontally and if the screw holes on the spacers are aligned with the expansion board screw holes, then you're set to use the remaining screws to tighten it down.
4. With the expansion properly tightened to the top board, I slid it back onto the pins and I was done.
I noticed that the bottom and top boards weren't screwed in and that the pins were the only thing bonding it together. I don't believe that the top and bottom boards would separate as a substantial amount of force is needed to pull them apart but I can see some people wanting to secure it down. These screws are not supplied unfortunately. The new banks sound amazing and this video doesn't really focus on that. Next time....
*4.13.10 Update: The official manual for installation and information can be found HERE.