you have a megasquirt, wht are you going to use it as a piggyback and not a standalone, for the price it is a waste to use it as a piggyback when you can get an AEM FIC which is a much better unit, it has a 21x17 fuel and ignition map as opposed to a 16x16, you can also set it up to use a map instead of an afm, you can cut fuel if you are running huge injectors. It is much more user friendly than the ms, and imo anything AEM is easy to tune, and if you go somewhere to get it tuned, they will be able to do it, every performance shop knows how to tune them, which saves you money because tuning is done by the hour.
http://www.aempower.com/ViewCategory.aspx?CategoryID=116