As the saying goes: Proper planning prevents piss poor performance. I loaded the .pdf for the MegaSquirt, the LC-1 Wideband, and the Dodge Shop Manual onto my tablet. I printed out the pin reference for all of the engine connectors, and I had various diagrams for the alternator, auto shutdown relay, and of course the MegaSquirt and MS3X.
I ordered an MS3 with the MS3X expansion board from SymTech Labs. If you go this route – I was a little confused as MegaSquirt also has a version 3.0 board. So you have a MegaSquirt 3 processor with a version 3.0 board and an MS3X – lots of M S and 3’s to confuse you. I initially thought the 3.0 board WAS the MS3X… (wrong) Then there is the MS3-Pro, which is basically an MS3 + MS3X + some extras – in a more compact case for more money. As of 2013 this is the newest version of MegaSquirt hardware you can buy.
The MS3X expansion board allows you to do all the cool stuff out of the box like launch control, boost, nitrous, sequential fueling, etc. Full sequential is where you can individually trigger the fuel injector on one cylinder for just that particular intake stroke. Common MegaSquirt setup does a “batch fire” where 2 injectors are opened at the same time. This is okay at full throttle as the time it takes for the fuel to travel down the head, it was already on the next intake stroke at 6,000-RPMs. At idle though you are just spraying fuel onto a closed valve every other time at 700-RPM. Not very good for economy and not that great for a steady idle. In order for it to work though, the MS3X needs to know where your camshaft is.