Need recommendation for a Carb for better MPG!

I haven't had any personal experience with a aftermarket EFI set up, but wouldn't something like that be the way to go? I've seen the self tuning units being used on garage squad and other shows and I've read some things about them. I don't remember the name of them but I do remember that it wasn't a holley. They all claim faster starting, improved performance and mileage and the fact that they are self tuning would make it worth checking on I would think.