A megasquirt system is compiled from a myriad of mid-'90's GM EFI parts, plus you get to really screw yourself even harder because you pretty much build it yourself, or buy one someone else made. The only really unique thing about it is the open source software that it runs on. There are several limitations of these systems however, that make it not suitable for use in high rpm engine. First, the common sampling limitation of the processor will only support a maximum effective redline of 11750rpm. Second, the injector pulse width supported by the drivers on the ECM and injectors themselves does not support a large displacement engine or and engine that has to twice as many injection events as the engine type it was originally designed for (2 stroke vs. 4 stroke). Finally, the thing that really drives me nuts about these systems is that the injectors drivers on the ECM are not on protected circuits, so any electrical issues in the system burn up the drivers, which make you by a new ECM. All of that makes it not the best choice for a Banshee engine, unless of course that it is all you are familiar with, but even then, you limit yourseld to what you can do with that engine when using one.
The MoTEC systems are nothing like an OEM FIS system. The software is is completely different (onboard and on-bench), the hardware is completely different, and it really isn't a knock-off of anything..........so, come on, how about we stop making stuff up here.