This DIY solution is a great way to jump into the world of EFI. It taught me the basics of how EFI works. You can find some great info at DIYautotune; i basically mimicked their carb-to-TBI tutorial on my 65 Valiant. MS is configurable to control just about any fuel and spark system. Tons of great resources at msextra; manuals and forum. The software that controls is TunerStudio. It's free but I highly suggest registering it to unlock great auto-tuning features and more importantly to support the developer.
Megasquirt 2 (MS2) is a popular and versatile system that can fuel a V8 in batch mode and has built in IAC control and a MAP sensor. MS3 supports sequential fuel which provides better fuel distribution. Microsquirt is another system; it's a great low-buck no frills solution to control a basic EFI system but doesn't control IAC nor does it have a MAP sensor. All of these systems can be used in turbo applications. Denmah has provided the world with a low-buck approach to slapping on a turbo on the LS series GM engines. His wiki can be found here and contains a wealth of information.
Controlling the later electronic transmissions is also possible with MS but requires you to buy another controller. I'm not venturing there in my builds since I plan to use either a stick shift or a vintage automatic. If controlling fuel, spark and the tranny are your goals, and you want to use the stock ECU you may want to look into HPtuners.
I'm using an MS2 on my '65 Valiant and it's currently only controlling fuel. Picked up a chevy van 350 TBI from a salvage yard, two GM coolant/temp sensors and a wideband AFR sensor. I also installed an in-tank high pressure pump in the stock tank from Tanks Inc. and ran some high-pressure fuel lines. It's a very basic system but the car starts everytime without touching the pedal. I also bought the bluetooth adapter so I can monitor all engine functions on a spare Android phone I had lying around.
Picked up a mid 80's electronic mopar distributor to control spark but the shaft was slightly bent. Haven't gotten around to picking up another one yet but I will eventually. This will allow MS2 to fully control the ignition advance over all RPMs and engine loads.
I have a early 2000's Magnum 5.2L waiting to drop in the Valiant at some point. Afterall, the 318 in the Valiant was a temporary motor, but it runs perfect and has great oil pressure. If it ain't broke...