I haven't started my car in a month or so. She's sitting outside. I bet I can hop in push the pedal once and she will fire right up, idle like I pulled two plug wires off and run like a striped *** ape with his balls on fire....
Now if I wanted MPG yeah EFI all day but I'm perfectly happy at 5 or 6 MPG. I didn't built a race car for MPG....
And performance engines don't get good mileage. Injected or not. Your choice. I have noticed some have issues getting everything to work with a big cam but that is with carbs or injection.